How can cannabis and cannabinoids help you? What the research says

Medical cannabis and cannabinoids in raw or dried flowers, oils, capsules, powders, edibles, and topicals may reduce pain, and some evidence shows benefit with nausea and anxiety, but little evidence of improving treatment outcomes.

How can cannabis and cannabinoids help you? What the research says

We summarize the clinical evidence for each medical benefit here. We begin with our assessment of the strength of evidence within each category, followed by a brief summary of individual studies or reviews of several studies. In assessing the strength of evidence, we consider the study design, number of participants, and the size of the treatment effect (how much outcomes changed with treatment).

To see more details, click the plus sign to the right of any section.

Our assessments of evidence for each medical benefit fall into one of these categories:

Strong evidence: consistent, significant effects in several large (or at least one very large) well designed clinical studies or at least two meta-analysesa statistical analysis that combines the results of two or more research studies; the results of smaller research studies addressing the same or similar questions can be analyzed as though they are one bigger, more powerful study of clinical studies of moderate or better quality (or one large meta-analysis) finding similar results
Good evidence: significant effects in one large or several mid-sized and well-designed clinical studies ( randomized controlled trialsa study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects with an appropriate placebo or other strong comparison control or observational studies that control for confounds)
Modest evidence: significant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods studies), or several small studies aggregated into a meta-analysis
Preliminary evidence: significant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect
Weak evidence: one or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects
Insufficient evidence: preclinical evidence only OR clinical studies with such poor or unclear methodology that no conclusion can be drawn OR conflicting findings across clinical studies with no preponderance of evidence in one direction; conflicting evidence occurs when studies find conflicting effects (positive effect vs no effect or negative effect) with the same treatment and the same general study population (same cancer type, for example)

Learn more about how we research and rate therapies and practices in How We Rate Therapies ›

A brief summary of preclinical evidence is in Are you a health professional? ›

Improving treatment outcomes

Is cannabis or cannabinoids linked to improved survival? Is it linked to less cancer growth or metastasis? Does it enhance the anticancer action of other treatments or therapies? We present the evidence.

Cancer as a whole

While some preclinical studiestesting a drug, a procedure, or another medical treatment in isolated cells or in animals; preclinical evidence is considered only an initial indication of possible effects in people have found that cannabis derivatives can kill tumor cells in a lab, clinical studies do not find that cannabis improves outcomes across different cancer types in humans.

No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on 5-year overall survival, disease-specific survival, or metastasis-free survival among people with oropharynx squamous cell carcinoma with cannabis use compared to no use in a small observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods study¹Zhang H, Xie M et al. Survival outcomes of marijuana users in p16 positive oropharynx cancer patients. Journal of Otolaryngology—Head and Neck Surgery. 2019 Sep 2;48(1):43.
Fewer circulating tumor cells and in some cases reduced tumor volume among people with cancer, mostly metastatic cancer, treated with synthetic, pharmaceutical-grade CBD or nabiximols as a source of THC given intermittently (3 days on, 3 days off) for 6 months or longer; people who reverted to commercial cannabis oil had an 80% relapse rate in case reportsa descriptive and exploratory analysis of a person, group, or event regarding changes observed over time; because changes due to treatment are not compared to similar changes over time without treatment, a case study is considered a weak study design²Kenyon J, Liu W, Dalgleish A. Report of objective clinical responses of cancer patients to pharmaceutical-grade synthetic cannabidiol. Anticancer Research. 2018 Oct;38(10):5831-5835./

Preclinical evidence is summarized here: Are you a health professional? ›

Also see evidence of worse outcomes among people treated with immunotherapy in Safety and precautions ›

Advanced cancer

No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments.: In a single clinical study, people with advanced cancer treated with CBD showed no benefit in progression or survival.

Brain cancer

Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently): People with glioblastoma treated with cannabis or synthetic cannabis showed better survival in two small studies.

Lung cancer

No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments.: There was no evidence of an effect on progression or survival among people with metastatic lung cancer treated with cannabis following standard treatment in one observational study.

Optimizing your body terrain

Does cannabis or cannabinoids promote an environment within your body that is less supportive of cancer development, growth, or spread? We present the evidence.

See Optimizing Your Body Terrain ›

Find medical professionals who specialize in managing body terrain factors: Finding Integrative Oncologists and Other Practitioners ›

We also recommend that you share with your doctor the information here about how cannabis or cannabinoids might affect these terrain factors if you have any imbalances.

High blood sugar and insulin resistance

Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently): People without cancer who had type 2 diabetes not treated with insulin showed lower fasting glucose levels when treated with a THC derivative in one study.

Inflammation

No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments.: There was no evidence of an effect on markers of inflammation among people with advanced cancer treated with CBD in one study.

Your microbiome

Insufficient evidencepreclinical evidence only OR clinical studies with such poor or unclear methodology that no conclusion can be drawn OR conflicting findings across clinical studies with no preponderance of evidence in one direction; conflicting evidence occurs when studies find conflicting effects (positive effect vs no effect or negative effect) with the same treatment and the same general study population (same cancer type, for example) (this is the CancerChoices definition; other researchers and studies may define this differently): People without cancer who smoked cannabis showed lower levels of mouth bacteria that are associated with head and neck cancer in one small study. This is inconclusive evidence, as we do not know whether these bacteria are a cause of cancer or a result.

Managing side effects and promoting wellness

Is cannabis or cannabinoids linked to fewer or less severe side effects or symptoms? Is it linked to less toxicity from cancer treatment? Does it support your quality of life or promote general well-being? We present the evidence.

Side effects as a whole

Weak evidenceone or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects (this is the CancerChoices definition; other researchers and studies may define this differently): There is no direct evidence that cannabis can help relieve side effects of cancer treatment overall.

Anxiety

Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently): Many people without cancer self-medicate for anxiety with cannabis, and cannabis appears to reduce anxiety symptoms in many people. However, there is insufficient evidencepreclinical evidence only OR clinical studies with such poor or unclear methodology that no conclusion can be drawn OR conflicting findings across clinical studies with no preponderance of evidence in one direction; conflicting evidence occurs when studies find conflicting effects (positive effect vs no effect or negative effect) with the same treatment and the same general study population (same cancer type, for example) (this is the CancerChoices definition; other researchers and studies may define this differently) of an effect on people with cancer, or of an effect on cancer-related anxiety. One large analysis also found that people with cancer who took high doses of THC had a higher risk of anxiety.

A greater risk of anxiety with higher doses of synthetic THC, but no evidence of an overall effect on depression or anxiety, among people with cancer treated with cannabis products in a combined analysis of 15 observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods studies¹¹Crichton M, Dissanayaka T et al. Does medicinal cannabis affect depression, anxiety, and stress in people with cancer? A systematic review and meta-analysis of intervention studies. Maturitas. 2024 Jun;184:107941.
Limited, insufficient or absent evidence supporting improvement in anxiety among people with cancer using cannabis or cannabinoids in a systematic review of recent (at that time) medical literature¹²Abrams DI. The therapeutic effects of cannabis and cannabinoids: an update from the National Academies of Sciences, Engineering and Medicine report. European Journal of Internal Medicine. 2018 Mar;49:7-11.
No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on anxiety among people with advanced breast cancer treated with a single 400mg dose of CBD 48 hours before a scan compared to placeboa pill, medicine, or procedure—thought to be both harmless and ineffective—prescribed for the psychological benefit to the patient or as a sham treatment in a study to allow a comparison to a therapy of interest in a small RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects¹³Nayak MM, Chai P et al. Cannabidiol for scan-related anxiety in women with advanced breast cancer: a randomized clinical trial. JAMA Network Open. 2024 Dec 2;7(12):e2450391.

Anxiety in people without cancer

Modest evidence: People without cancer treated with THC, with or without CBD, showed fewer anxiety symptoms in a combined analysis of studies.

Fewer anxiety symptoms among people with non-cancer medical conditions (primarily chronic non-cancer pain and multiple sclerosis) treated with pharmaceutical THC either with or without CBD compared to controls in a meta-analysisa statistical analysis that combines the results of two or more research studies; the results of smaller research studies addressing the same or similar questions can be analyzed as though they are one bigger, more powerful study of 31 RCTs and other clinical trials of low quality¹⁴Black N, Stockings E et al. Cannabinoids for the treatment of mental disorders and symptoms of mental disorders: a systematic review and meta-analysis. Lancet Psychiatry. 2019 Dec;6(12):995-1010.

Many people without cancer self-medicate for anxiety with cannabis¹⁵Beletsky A, Liu C et al. Cannabis and anxiety: a critical review. Medical Cannabis and Cannabinoids. 2024 Feb 23;7(1):19-30., and cannabis appears to reduce anxiety symptoms in many people.¹⁶Berger M, Amminger GP, McGregor IS. Medicinal cannabis for the treatment of anxiety disorders. Australian Journal of General Practice. 2022 Aug;51(8):586-592.

Changes in appetite

Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently): Two studies find that cannabis can help preserve the sense of taste among people receiving chemotherapy, and a combined analysis of 15 studies found that people with cancer treated with THC showed better appetite, though some other studies have not found this effect.

Weak evidenceone or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects (this is the CancerChoices definition; other researchers and studies may define this differently) of better appetite among people with cancer-related loss of appetite treated with cannabis (dronabinol, nabilone and cannabis extract) compared to placeboa pill, medicine, or procedure—thought to be both harmless and ineffective—prescribed for the psychological benefit to the patient or as a sham treatment in a study to allow a comparison to a therapy of interest in a combined analysis of 5 RCTsrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects¹⁷Razmovski-Naumovski V, Luckett T et al. Efficacy of medicinal cannabis for appetite-related symptoms in people with cancer: A systematic review. Palliative Medicine. 2022 Jun;36(6):912-927.
Better appetite among people with cancer treated with cannabis products containing THC in a combined analysis of 15 observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods studies¹⁸Crichton M, Dissanayaka T et al. Does medicinal cannabis affect depression, anxiety, and stress in people with cancer? A systematic review and meta-analysis of intervention studies. Maturitas. 2024 Jun;184:107941.
Weak evidence of better self-reported appetite, but no evidence of weight gain, among people with cancer-related cachexia treated with cannabis a combined analysis of 10 studies of mixed type¹⁹Simon L, Baldwin C, Kalea AZ, Slee A. Cannabinoid interventions for improving cachexia outcomes in cancer: a systematic review and meta-analysis. Journal of Cachexia, Sarcopenia, and Muscle. 2022 Feb;13(1):23-41.
Better ability to distinguish different tastes among people receiving oxaliplatin- or paclitaxel- based chemotherapy (both of which can cause loss of taste) and treated with 300mg oral CBD daily in a small RCT²⁰Dominiak HSH, Hasselsteen SD et al. Prevention of taste alterations in patients with cancer receiving paclitaxel- or oxaliplatin-based chemotherapy-A pilot trial of cannabidiol. Nutrients. 2023 Jul 1;15(13):3014.
Improved and enhanced chemosensory perception and reports that food ‘tasted better’ among adults with advanced cancer treated with 2.5 mg THC (Marinol) compared to placebo in a small RCT²¹Brisbois TD, de Kock IH et al. Delta-9-tetrahydrocannabinol may palliate altered chemosensory perception in cancer patients: results of a randomized, double-blind, placebo-controlled pilot trial. Annals of Oncology. 2011 Sep;22(9):2086-2093.

Gastrointestinal effects

Strong evidenceconsistent, significant effects in several large (or at least one very large) well designed clinical studies or at least two meta-analyses of clinical studies of moderate or better quality (or one large meta-analysis) finding similar results (this is the CancerChoices definition; other researchers and studies may define this differently) of less nausea and vomiting: People treated with synthetic cannabis and cannabis-derived medications had less nausea and vomiting during chemotherapy across several combined analyses of studies. Many combined analyses also found that cannabis relieved nausea and vomiting better than pharmacological treatments; however, these studies were mostly conducted on anti-nausea treatments that are now outdated. Some studies also found that pharmaceutical cannabinoids were less tolerated and less safe than placebo.

Less nausea and vomiting among undergoing chemotherapy who were treated with cannabis-derived drugs compared to placeboa pill, medicine, or procedure—thought to be both harmless and ineffective—prescribed for the psychological benefit to the patient or as a sham treatment in a study to allow a comparison to a therapy of interest in a combined analysis of 26 controlled trialsa study design in which people are assigned to either an experimental group or a control group to compare the outcomes from different treatment; assignment is not random, and so this is not as strong a study design as a randomized controlled trial, but still stronger than an uncontrolled trial conducted mostly before 2003. There was no evidence of an effect compared to the anti-nausea drugs alizapride, chlorpromazine, dexamethasone, and prochlorperazine, which were mostly used singly before the 2000s; modern antinausea regimens combine these medications and others²²Chow R, Basu A et al. Efficacy of cannabinoids for the prophylaxis of chemotherapy-induced nausea and vomiting-a systematic review and meta-analysis. Supportive Care in Cancer. 2025 Feb 14;33(3):193.
Less nausea and vomiting during chemotherapy among adults with nausea or vomiting that did not respond to other medication who were treated with 7.5 mg THC plus 7.5 mg CBD capsules compared to placebo in a mid-sized RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects²³Grimison P, Mersiades A et al. Oral cannabis extract for secondary prevention of chemotherapy-induced nausea and vomiting: final results of a randomized, placebo-controlled, phase II/III trial. Journal of Clinical Oncology. 2024 Aug 16:JCO2301836.
Less chemotherapy-induced nausea and vomiting overall, but no evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on nausea alone or vomiting alone, among people treated with oral cannabis compared to placebo or other treatments in a meta-analysisa statistical analysis that combines the results of two or more research studies; the results of smaller research studies addressing the same or similar questions can be analyzed as though they are one bigger, more powerful study of 5 RCTs²⁴Chow R, Valdez C, Chow N, et al. Oral cannabinoid for the prophylaxis of chemotherapy-induced nausea and vomiting—a systematic review and meta-analysis. Supportive Care in Cancer. 2020;28:2095-2103.
A weak trendan apparent change due to a therapy, close to but not achieving full statistical significance (this is the CancerChoices definition; other researchers and studies may define this differently toward less nausea and vomiting among people with cancer treated with cannabis or cannabinoids compared to placebo in a meta-analysis of 9 RCTs and controlled trials²⁵Mücke M, Carter C et al. Cannabinoide in der palliativen Versorgung: Systematische Übersicht und Metaanalyse der Wirksamkeit, Verträglichkeit und Sicherheit [Cannabinoids in palliative care: systematic review and meta-analysis of efficacy, tolerability and safety]. Schmerz. 2016 Feb;30(1):25-36. German.
No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on nausea and vomiting among people with cancer treated with cannabinoids compared to placebo in a meta-analysis of 9 RCTs of low quality²⁶Mücke M, Weier M. Systematic review and meta-analysis of cannabinoids in palliative medicine. Journal of Cachexia, Sarcopenia and Muscle. 2018 Apr;9(2):220-234.
Less vomiting, though mixed effects on nausea, during chemotherapy treatment among people treated with cannabinoids compared to placebo in a meta-analysis of 3 RCTs of low quality²⁷Smith LA, Azariah F, Lavender VT, Stoner NS, Bettiol S. Cannabinoids for nausea and vomiting in adults with cancer receiving chemotherapy. Cochrane Database or Systematic Reviews. 2015 Nov 12;2015(11):CD009464.
A very weak trend toward less vomiting during chemotherapy among people with cancer treated with dronabinol compared to placebo in a combined analysis of a subset of 30 RCTs²⁸Machado Rocha FC, Stéfano SC, De Cássia Haiek R, Rosa Oliveira LM, Da Silveira DX. Therapeutic use of Cannabis sativa on chemotherapy-induced nausea and vomiting among cancer patients: systematic review and meta-analysis. European Journal of Cancer Care (England). 2008 Sep;17(5):431-43.
A lower risk of developing chemotherapy-induced nausea and vomiting that did not respond to medication among people treated with self-titrated 7.5-30 mg oral THC and 7.5-30 mg CBD compared to placebo in a small RCT;²⁹Grimison P, Mersiades A et al. Oral THC:CBD cannabis extract for refractory chemotherapy-induced nausea and vomiting: a randomised, placebo-controlled, phase II crossover trial. Annals of Oncology. 2020;31:1553-1560. this study also found a higher rate of side effects, as noted in Safety and precautions ›
No difference in the number of people reporting nausea and vomiting during chemotherapy treatment among people treated with cannabinoids compared to prochlorperazine in a meta-analysis of 5 RCTs of low quality³⁰Smith LA, Azariah F, Lavender VT, Stoner NS, Bettiol S. Cannabinoids for nausea and vomiting in adults with cancer receiving chemotherapy. Cochrane Database or Systematic Reviews. 2015 Nov 12;2015(11):CD009464.
Less vomiting during chemotherapy treatment among people with cancer treated with dronabinol or nabilone compared to neuroleptics in meta-analyses of a subset of 30 RCTs³¹Machado Rocha FC, Stéfano SC, De Cássia Haiek R, Rosa Oliveira LM, Da Silveira DX. Therapeutic use of Cannabis sativa on chemotherapy-induced nausea and vomiting among cancer patients: systematic review and meta-analysis. European Journal of Cancer Care (England). 2008 Sep;17(5):431-43.
Less chemotherapy-induced nausea and vomiting among people treated with oral synthetic THC (dronabinol or nabilone) or edible cannabis compared to placebo or other treatments in a meta-analysis of 5 RCTs³²Chow R, Valdez C, Chow N, et al. Oral cannabinoid for the prophylaxis of chemotherapy-induced nausea and vomiting—a systematic review and meta-analysis. Supportive Care in Cancer. 2020;28:2095-2103.

Some studies also found that pharmaceutical cannabinoids were less tolerated and less safe than placebo, as noted in Safety and precautions ›

Pain

Modest evidence: Several combined analyses of studies have found reduced pain among people with cancer-related pain treated with cannabis, although the effect was sometimes quite small, and a few analyses did not find this effect. The type of cannabis product (THC or CBD) and the dose varied widely across studies. There is preliminary evidence that people with cancer treated with cannabis required a lower dose of opioid pain medications. There is good evidencesignificant effects in one large or several mid-sized and well-designed clinical studies (randomized controlled trials (RCTs) with an appropriate placebo or other strong comparison control or observational studies that control for confounds) (this is the CancerChoices definition; other researchers and studies may define this differently) that cannabis can help with pain not related to cancer.

People with advanced cancer treated with medical cannabis oil (escalating from 2.5mg THC and 2.5 mg CBD to 30 mg THC and 30 mg THC daily) showed less pain compared to placeboa pill, medicine, or procedure—thought to be both harmless and ineffective—prescribed for the psychological benefit to the patient or as a sham treatment in a study to allow a comparison to a therapy of interest in a mid-sized RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects. However, these people also had a higher risk of hallucination and other psychological side effects of cannabis.³³Hardy JR, Greer RM et al. Medicinal cannabis for symptom control in advanced cancer: a double-blind, placebo-controlled, randomised clinical trial of 1:1 tetrahydrocannabinol and cannabidiol. Supportive Care in Cancer. 2025 Jul 24;33(8):715.
Less pain among people with cancer-related bone pain treated with cannabis (medical cannabis, delta-9 THC, or NIB, a synthetic cannabinoid) compared to placebo in a combined analysis of 35 studies³⁴Zeng F, Wade A et al. Classical cannabinoid receptors as target in cancer-induced bone pain: a systematic review, meta-analysis and bioinformatics validation. Scientific Reports. 2024 Mar 9;14(1):5782.
No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on pain among people with cancer treated with medical cannabis or THC- and CBD – based medicines compared to conventional pain medications in a combined analysis of 14 RCTs, several of which may be outdated³⁵Häuser W, Welsch P, Radbruch L, Fisher E, Bell RF, Moore RA. Cannabis-based medicines and medical cannabis for adults with cancer pain. Cochrane Database of Systematic Reviews. 2023 Jun 5;6(6):CD014915.
Weak evidenceone or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects (this is the CancerChoices definition; other researchers and studies may define this differently) that people with chronic or cancer-related pain treated with oral or topical cannabis had reduced pain in a combined analysis of 32 RCTs³⁶Wang L, Hong PJ et al. Medical cannabis or cannabinoids for chronic non-cancer and cancer related pain: a systematic review and meta-analysis of randomised clinical trials. BMJ. 2021 Sep 8;374:n1034.
People with stage 4 cancer who were treated with medical cannabis early (at an average dose of 34mg THC and 17mg CBD) had lower pain and needed a lower dose of opiate pain medication in a small RCT³⁷Zylla DM, Eklund J et al. A randomized trial of medical cannabis in patients with stage IV cancers to assess feasibility, dose requirements, impact on pain and opioid use, safety, and overall patient satisfaction. Supportive Care in Cancer. 2021 Dec;29(12):7471-7478.
Lower cancer-related pain scores among people with pain treated with oramucosal THC/CBD or THC alone (inserted between the cheek and gum) or inhaled dried cannabis compared to controls in a meta-analysisa statistical analysis that combines the results of two or more research studies; the results of smaller research studies addressing the same or similar questions can be analyzed as though they are one bigger, more powerful study of a subset of 25 RCTs³⁸Rabgay K, Waranuch N et al. The effects of cannabis, cannabinoids, and their administration routes on pain control efficacy and safety: a systematic review and network meta-analysis. Journal of the American Pharmacists Association. 2020 Jan-Feb;60(1):225-234.e6.
A weak trendan apparent change due to a therapy, close to but not achieving full statistical significance (this is the CancerChoices definition; other researchers and studies may define this differently toward a 30% or greater decrease in pain among people with cancer treated with cannabis or cannabinoids compared to placebo in 2 meta-analyses each combining 9 RCTs and controlled trialsa study design in which people are assigned to either an experimental group or a control group to compare the outcomes from different treatment; assignment is not random, and so this is not as strong a study design as a randomized controlled trial, but still stronger than an uncontrolled trial of low quality³⁹Mücke M, Carter C et al. Cannabinoide in der palliativen Versorgung: Systematische Übersicht und Metaanalyse der Wirksamkeit, Verträglichkeit und Sicherheit [Cannabinoids in palliative care: systematic review and meta-analysis of efficacy, tolerability and safety]. Schmerz. 2016 Feb;30(1):25-36. German; Mücke M, Weier M. Systematic review and meta-analysis of cannabinoids in palliative medicine. Journal of Cachexia, Sarcopenia and Muscle. 2018 Apr;9(2):220-234.
Lower pain scores among people with pain—the majority with neuropathic pain—treated with synthetic THC in a meta-analysis of 6 RCTs⁴⁰McDonagh MS, Morasco BJ et al. Cannabis-based products for chronic pain: a systematic review. Annals of Internal Medicine. 2022 Jun 7.
No evidence of an effect on chronic cancer pain among people treated with cannabis in addition to prescription opioids in a combined analysis of 5 RCTs⁴¹Noori A, Miroshnychenko A et al. Opioid-sparing effects of medical cannabis or cannabinoids for chronic pain: a systematic review and meta-analysis of randomised and observational studies. BMJ Open. 2021 Jul 28;11(7):e047717.
Lower opioid use among people with chronic cancer pain treated with prescription opioids and cannabis compared to opioids alone in a meta-analysis of 12 observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods studies⁴²Noori A, Miroshnychenko A et al. Opioid-sparing effects of medical cannabis or cannabinoids for chronic pain: a systematic review and meta-analysis of randomised and observational studies. BMJ Open. 2021 Jul 28;11(7):e047717.
People with advanced cancer treated with a combination of CBD (40-80mg) and THC (1.5-3mg) in addition to prescription opioids had reduced pain over time in an uncontrolled triala study in which a therapy is used, but without a comparison group against which to judge outcomes; an uncontrolled trial is considered a weak study design⁴³Zanker T, Sacco J et al. Medical marijuana for pain management in hospice care as a complementary approach to scheduled opioids: a single arm study. American Journal of Hospice and Palliative Care. 2024 Sep;41(9):1002-1010.
People with advanced cancer treated with medical cannabis oil (5mg CBD and 5mg THC daily) showed less pain compared to placebo in a mid-sized RCT⁴⁴Hardy JR, Greer RM et al. Medicinal cannabis for symptom control in advanced cancer: a double-blind, placebo-controlled, randomised clinical trial of 1:1 tetrahydrocannabinol and cannabidiol. Supportive Care in Cancer. 2025 Jul 24;33(8):715.

Pain not related to cancer

Good evidencesignificant effects in one large or several mid-sized and well-designed clinical studies (randomized controlled trials (RCTs) with an appropriate placebo or other strong comparison control or observational studies that control for confounds) (this is the CancerChoices definition; other researchers and studies may define this differently): People with non-cancer-related pain showed lower pain scores across several studies, and less opioid use in one study.

Moderately lower pain scores among people with pain—the majority with neuropathic pain—treated with synthetic cannabinoids exclusively THC compared to controls in a meta-analysis of 6 RCTs⁴⁵McDonagh MS, Morasco BJ et al. Cannabis-based products for chronic pain: a systematic review. Annals of Internal Medicine. 2022 Jun 7.
Lower pain from physical damage (nociceptive pain) among people treated with oral standardized cannabis extract compared to controls in a meta-analysis of 25 RCTs⁴⁶Rabgay K, Waranuch N et al. The effects of cannabis, cannabinoids, and their administration routes on pain control efficacy and safety: a systematic review and network meta-analysis. Journal of the American Pharmacists Association. 2020 Jan-Feb;60(1):225-234.e6.
Less opioid use (greater reduction in use) among people receiving opioid treatment for chronic pain also treated with medical cannabis for at least 30 days compared to less than 30 days in a very large observational study⁴⁷Nguyen T, Li Y, Greene D, Stancliff S, Quackenbush N. Changes in prescribed opioid dosages among patients receiving medical cannabis for chronic pain, New York State, 2017-2019. JAMA Network Open. 2023 Jan 3;6(1):e2254573.

Quality of life and function

Mixed (insufficient) evidencepreclinical evidence only OR clinical studies with such poor or unclear methodology that no conclusion can be drawn OR conflicting findings across clinical studies with no preponderance of evidence in one direction; conflicting evidence occurs when studies find conflicting effects (positive effect vs no effect or negative effect) with the same treatment and the same general study population (same cancer type, for example) (this is the CancerChoices definition; other researchers and studies may define this differently): People with cancer treated with cannabis showed better quality of life in some domains (physical functioning and pain), but no change in social or emotional wellbeing, across several studies.

Sexual difficulties

Preliminary evidence: People recovering from treatment for gynecological cancer who used vaginal cannabis suppositories had less pain during sex in one study.

Sleep disruption

Mixed (insufficient) evidence: Some people with cancer-related pain who were treated with cannabis showed better sleep quality, but other studies did not find that cannabis improved sleep among people with cancer.

A small improvement in sleep quality among people with chronic pain or cancer treated with oral cannabis or cannabinoids compared to placeboa pill, medicine, or procedure—thought to be both harmless and ineffective—prescribed for the psychological benefit to the patient or as a sham treatment in a study to allow a comparison to a therapy of interest in a meta-analysisa statistical analysis that combines the results of two or more research studies; the results of smaller research studies addressing the same or similar questions can be analyzed as though they are one bigger, more powerful study of 32 RCTsrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects⁵³Wang L, Hong PJ et al. Medical cannabis or cannabinoids for chronic non-cancer and cancer related pain: a systematic review and meta-analysis of randomised clinical trials. BMJ. 2021 Sep 8;374:n1034.
People with cancer pain treated with cannabis showed no improvement in sleep on average, though people whose sleep improved were more likely to report a large improvement than those not treated with cannabis, in a combined-analysis of 5 RCTs of low quality⁵⁴Häuser W, Welsch P, Klose P, Radbruch L, Fitzcharles MA. Efficacy, tolerability and safety of cannabis-based medicines for cancer pain : a systematic review with meta-analysis of randomised controlled trials. Schmerz. 2019 Oct;33(5):424-436. English
No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on sleep problems among people with cancer treated with cannabis or cannabinoids compared to placebo in a meta-analysis of 9 RCTs and controlled trialsa study design in which people are assigned to either an experimental group or a control group to compare the outcomes from different treatment; assignment is not random, and so this is not as strong a study design as a randomized controlled trial, but still stronger than an uncontrolled trial⁵⁵Mücke M, Carter C et al. Cannabinoide in der palliativen Versorgung: Systematische Übersicht und Metaanalyse der Wirksamkeit, Verträglichkeit und Sicherheit [Cannabinoids in palliative care: systematic review and meta-analysis of efficacy, tolerability and safety]. Schmerz. 2016 Feb;30(1):25-36. German.
Little or no evidence of an effect on sleep disturbance among people with chronic cancer pain treated with prescription opioids and cannabis to compared to opioids alone in a combined analysis of 5 randomized trials⁵⁶Noori A, Miroshnychenko A et al. Opioid-sparing effects of medical cannabis or cannabinoids for chronic pain: a systematic review and meta-analysis of randomised and observational studies. BMJ Open. 2021 Jul 28;11(7):e047717.

Reducing cancer risk

Is cannabis or cannabinoids linked to lower risks of developing cancer or of recurrence? We present the evidence.

Cancer as a whole

Mixed (insufficient) evidencepreclinical evidence only OR clinical studies with such poor or unclear methodology that no conclusion can be drawn OR conflicting findings across clinical studies with no preponderance of evidence in one direction; conflicting evidence occurs when studies find conflicting effects (positive effect vs no effect or negative effect) with the same treatment and the same general study population (same cancer type, for example) (this is the CancerChoices definition; other researchers and studies may define this differently): A large analysis of studies found weak evidence of a lower overall cancer risk among people who used cannabis.

Head, neck, and oral cancer

Recurrence

No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments.: People who had survived oropharyngeal squamous cell carcinoma and used cannabis showed no evidence of an effect on recurrence in a small study.

Keep reading about cannabis and cannabinoids

See all our reviews of complementary therapies

Authors

Sophie Kakarala

Research Assistant

View profile

Nancy Hepp, MS

past Lead Researcher

View profile

Laura Pole, MSN, RN, OCNS

Senior Clinical Consultant

View profile

Reviewer

Donald I. Abrams, MD

Integrative oncologist, author, and CancerChoices advisor

View profile

Last update: November 17, 2025

Last full literature review: October 2025

We are grateful to integrative oncologist and CancerChoices advisor Donald Abrams, MD, for his generous sharing of research articles and commentary.

CancerChoices provides information about integrative in cancer care, a patient-centered approach combining the best of conventional care, self care and evidence-informed complementary care in an integrated plan cancer care. We review complementaryin cancer care, complementary care involves the use of therapies intended to enhance or add to standard conventional treatments; examples include supplements, mind-body approaches such as yoga or psychosocial therapy, and acupuncture therapies and self-care lifestyle actions and behaviors that may impact cancer outcomes; examples include eating health-promoting foods, limiting alcohol, increasing physical activity, and managing stress practices to help patients and professionals explore and integrate the best combination of conventionalthe cancer care offered by conventionally trained physicians and most hospitals; examples are chemotherapy, surgery, and radiotherapy and complementary therapies and practices for each person.

Our staff have no financial conflicts of interest to declare. We receive no funds from any manufacturers or retailers gaining financial profit by promoting or discouraging therapies mentioned on this site.

CancerChoices and BCCT Take: Cannabis and Head and Neck Cancer

References[+]

Cannabis and Cannabinoids (Marijuana)

How can cannabis and cannabinoids help you? What the research says

Improving treatment outcomes

Optimizing your body terrain

Managing side effects and promoting wellness

Reducing cancer risk

Keep reading about cannabis and cannabinoids

Authors

Sophie Kakarala

Nancy Hepp, MS

Laura Pole, MSN, RN, OCNS

Reviewer

Donald I. Abrams, MD

Learn more

Getting a Clear Picture of Research on Cancer Therapies

Electroacupuncture

CancerChoices and BCCT Take: Cannabis and Head and Neck Cancer