Turmeric and Curcumin: Safety and precautions - CancerChoices

Turmeric, with the active component curcumin, is both a food and a dietary supplement that may promote a better immune response and blood sugar levels, and may also help you manage some side effects of cancer.

Safety and precautions

Curcumin is generally regarded as safe by the US Food and Drug Administration (FDA). Medical supervision is recommended at doses higher than those typically found in foods.

Epidemiological evidence and several clinical trials have found minimal side effects with oral curcumin up to 12 grams per day over several months.1Lao CD, Rufin MT et al. Dose escalation of a curcuminoid formulation. BMC Complementary and Alternative Medicine 2006;6:10. Short-term intravenous use of liposomalvery tiny, fat-like particles used as delivery enhancers for some vitamins, minerals, and micronutrients to improve transport into the bloodstream curcumin appears to be safe up to a dose of 120 mg/m2. Changes in red blood cells may indicate toxicity at higher doses.2Storka A, Vcelar B et al. Safety, tolerability and pharmacokinetics of liposomal curcumin in healthy humans. International Journal of Clinical Pharmacology and Therapeutics. 2015 Jan;53(1):54-65.

Conflicting evidence of toxicity at 8,000 mg/day:

  • No toxicity in people with high risk of cancer or premalignant lesions treated with oral curcumin up to 8,000 mg/day for 3 months in a small clinical trial3Cheng AL, Hsu CH et al. Phase I clinical trial of curcumin, a chemopreventive agent, in patients with high-risk or pre-malignant lesions. Anticancer Research. 2001 Jul-Aug;21(4B):2895-900. 
  • Low compliance due to intractable abdominal fullness or pain among people with advanced pancreatic cancer with 8 g oral curcumin daily, concurrently with gemcitabine 1,000 mg/m(2) IV weekly × 3 of 4 weeks in a small uncontrolled triala study in which a therapy is used, but without a comparison group to judge outcomes against; an uncontrolled trial is considered a weak study design4Epelbaum R, Schaffer M, Vizel B, Badmaev V, Bar-Sela G. Curcumin and gemcitabine in patients with advanced pancreatic cancer. Nutrition and Cancer. 2010;62(8):1137-41. 
  • 100% compliance and no withdrawals due to toxicity among people with gemcitabine-resistant pancreatic cancer taking 8 g oral curcumin daily in combination with gemcitabine-based chemotherapy in a small uncontrolled trial5Kanai M, Yoshimura K et al. A phase I/II study of gemcitabine-based chemotherapy plus curcumin for patients with gemcitabine-resistant pancreatic cancer. Cancer Chemotherapy and Pharmacology. 2011 Jul;68(1):157-64. 

Side effects or adverse events

Side effects are mostly associated with doses higher than four grams per day:6Fadus MC, Lau C, Bikhchandani J, Lynch HT. Curcumin: an age-old anti-inflammatory and anti-neoplastic agent. Journal of Traditional and Complementary Medicine. 2016 Sep 9;7(3):339-346.

  • Mild and self-resolving gastrointestinal disturbances such as loose stools, reflux, bloating, and abdominal discomfort
  • Decreased iron levels
  • Temporary rise in liver enzymes
  • Suppressed platelet aggregation, possibly leading to bleeding
  • Contact dermatitis, hives (urticaria)

In rare cases, extended use can cause stomach upset or heartburn7Weil A. Curcumin or turmeric? Andrew Weil, MD. Viewed October 11, 2021. or even liver damage.8Cooperman T. Turmeric and Curcumin Supplements and Spices Review. ConsumerLab.com. Viewed December 5, 2023.

Interactions with other therapies

Curcumin can interact with chemotherapy drugs such as cyclophosphamide and doxorubicin.9Yeung KS, Gubili J, Mao JJ. Herb-drug interactions in cancer care. Oncology (Williston Park). 2018 Oct 15;32(10):516-20. Do not take curcumin if you are receiving the chemotherapy drugs cyclophosphamide, irinotecan, or camptothecin. If you are using other chemotherapy drugs, check with your oncology team about use.10McKinney N. Naturopathic Oncology, 3rd Edition. Victoria, BC, Canada: Liaison Press. 2016.

Two deaths from multiple organ failure occurred during the 3 months after treatment ended among women with advanced and metastatic breast cancer treated with paclitaxel and 300 mg intravenous solution curcumin once per week compared to no deaths with paclitaxel and placebo in a mid-sized RCT; the investigator assessed that these deaths were not related to curcumin treatment.11Saghatelyan T, Tananyan A et al. Efficacy and safety of curcumin in combination with paclitaxel in patients with advanced, metastatic breast cancer: a comparative, randomized, double-blind, placebo-controlled clinical trial. Phytomedicine. 2020 Apr 18;70:153218.

Piperine can slow the elimination of some prescription drugs including phenytoin (Dilantin), propranolol (Inderal), and theophylline. Curcumin can interfere with certain chemotherapy drugs used to treat breast cancer, so if you’re undergoing chemotherapy be sure to consult your physician about taking turmeric or curcumin during treatment.12Weil A. Curcumin or turmeric? Andrew Weil, MD. Viewed October 11, 2021.

Preliminary evidence in humans shows that cucrumin may slightly reduce the effectiveness of tamoxifen. In a study of people with breast cancer, researchers gave tamoxifen with or without curcumin, 1200 mg three times a day. The group taking tamoxifen in combination with curcumin had about an 8% decrease in endoxifen levels. If the curcumin was compounded with piperine (often done to substantially improve curcumin absorption), endoxifen levels were further decreased, by 12%.13Hussaarts KGAM, Hurkmans DP et al. Impact of curcumin (with or without piperine) on the pharmacokinetics of tamoxifen. Cancers (Basel). 2019 Mar 22;11(3). pii: E403. Read more about this study and implications for use during tamoxifen treatment in the Expert commentary section in How do experts use turmeric and curcumin? ›

Similarly, the TRC Natural Medicines database lists several interactions with chemotherapy drugs, diabetes medications and other drugs that lower blood sugar, estrogens, drugs that slow blood clotting, and other drugs.

Curcumin can interfere with certain liver detoxification enzymes and interact with substrates of drugs.14Fadus MC, Lau C, Bikhchandani J, Lynch HT. Curcumin: an age-old anti-inflammatory and anti-neoplastic agent. Journal of Traditional and Complementary Medicine. 2016 Sep 9;7(3):339-346.

Do not use (contraindications)

Stop use before surgery, as curcumin can increase bleeding. 

Compounds in curcumin can bind to iron and reduce iron’s availability, a concern to people with anemia or iron-storage problems. Iron levels may need to be monitored with curcumin supplement use, even among those with subclinical anemia or iron deficiency. Curcumin should therefore be taken with caution among those with marginally low iron stores or other diseases associated with iron such as anemia or chronic disease. Similarly, curcumin may possibly contribute to iron chelation, with the potential to cause a clinical or subclinical iron deficiency anemia.15ConsumerLab.com Answers. Is it true that taking turmeric/curcumin with food can reduce iron absorption from food? July 25, 2017. Viewed October 11, 2021; Fadus MC, Lau C, Bikhchandani J, Lynch HT. Curcumin: an age-old anti-inflammatory and anti-neoplastic agent. Journal of Traditional and Complementary Medicine. 2016 Sep 9;7(3):339-346.

Curcumin has antiplatelet properties, possibly increasing the risk of bleeding among people taking anti-clotting drugs.16Fadus MC, Lau C, Bikhchandani J, Lynch HT. Curcumin: an age-old anti-inflammatory and anti-neoplastic agent. Journal of Traditional and Complementary Medicine. 2016 Sep 9;7(3):339-346.

Cautions from integrative oncologist experts:17Weil A. Curcumin or turmeric? Andrew Weil, MD. Viewed October 11, 2021; Alschuler LN, Gazella KA. The Definitive Guide to Cancer, 3rd Edition: An Integrative Approach to Prevention, Treatment, and Healing. Berkeley, California: Celestial Arts. 2010; McKinney N. Naturopathic Oncology, 3rd Edition. Victoria, BC, Canada: Liaison Press. 2016.

Don’t use turmeric if you have gallstones, bile duct dysfunction (including biliary obstruction), hyperacidity, or stomach ulcers.

Pregnant or lactating women shouldn’t use turmeric supplements without their doctors’ approval. Curcumin should not be taken with these drugs:

  • Anastrozole
  • Cyclophosphamide
  • Erlotinib
  • Exemestane
  • Letrozole
  • Warfarin in therapeutic doses

Keep reading about turmeric and curcumin


Nancy Hepp, MS

Lead Researcher
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Ms. Hepp is a researcher and communicator who has been writing and editing educational content on varied health topics for more than 20 years. She serves as lead researcher and writer for CancerChoices and also served as the first program manager. Her graduate work in research and cognitive psychology, her master’s degree in instructional design, and her certificate in web design have all guided her in writing and presenting information for a wide variety of audiences and uses. Nancy’s service as faculty development coordinator in the Department of Family Medicine at Wright State University also provided experience in medical research, plus insights into medical education and medical care from the professional’s perspective.

Nancy Hepp, MS Lead Researcher

Dr. Ryan served as a research associate for CancerChoices. She is a licensed and board certified naturopathic physician and acupuncturist in Oregon. Dr. Ryan is the founder of Gentle Natural Wellness, a clinic specializing in bridging classical Chinese medicine with naturopathic medicine to provide individualized, compassionate care for people in the community. A Doctorate of Naturopathic Medicine and Master of Science in Oriental Medicine with honors from the National University of Natural Medicine, research in medical anthropology at the University of Hawai’i and George Mason University, language and culture programs at Obirin University (Tokyo) and Sogang University (Seoul), and studies of Chinese herbal medicine and qigong in China have provided a diverse background that has helped form a foundation for her community health and healing path.

Emily Ryan, ND, MSOM, LAc Research Associate


Laura Pole, MSN, RN, OCNS

Senior Clinical Consultant
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Laura Pole is senior clinical consultant for CancerChoices. Laura is an oncology clinical nurse specialist who has been providing integrative oncology clinical care, navigation, consultation, and education services for over 40 years. She is the co-creator and co-coordinator of the Integrative Oncology Navigation Training at Smith Center for Healing and the Arts in Washington, DC. Laura also manages the “Media Watch Cancer News That You Can Use” listserv for Smith Center/Commonweal. In her role as a palliative care educator and consultant, Laura has served as statewide Respecting Choices Faculty for the Virginia POST (Physician Orders for Scope of Treatment) Collaborative as well as provided statewide professional education on palliative and end-of-life care for the Virginia Association for Hospices and Palliative Care.

For CancerChoices, Laura curates content and research, networks with clinical and organizational partners, brings awareness and education of integrative oncology at professional and patient conferences and programs, and translates research into information relevant to the patient experience as well as clinical practice.

Laura sees her work with CancerChoices as a perfect alignment of all her passions, knowledge and skills in integrative oncology care. She is honored to serve you.

Laura Pole, MSN, RN, OCNS Senior Clinical Consultant

Last update: May 10, 2024

Last full literature review: October 2021

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.

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