Grapes and products made from grapes may promote body terrainthe internal conditions of your body, including nutritional status, fitness, blood sugar balance, hormone balance, inflammation and more factors known to be important in cancer, including better blood sugar and insulin levels and less oxidative stressan imbalance between free radicals and antioxidants in your body in which antioxidant levels are lower than normal; this imbalance can cause harmful oxidation reactions in your body chemistry.

Safety and precautions

Side effects or adverse events

Side effects reported in studies have typically been uncommon and mild:1Bitting RL, Tooze JA et al. Phase I study of muscadine grape extract for patients with advanced cancer. American Journal of Clinical Oncology. 2021 Jun 1;44(6):239-246; Mao JT, Lu QY et al. A pilot study of a grape seed procyanidin extract for lung cancer chemoprevention. Cancer Prevention Research (Philadelphia). 2019 Aug;12(8):557-566; Kessler ER, Su LJ et al. Phase II trial of acai juice product in biochemically recurrent prostate cancer. Integrative Cancer Therapies. 2018 Dec;17(4):1103-1108; Paller CJ, Rudek MA et al. A phase I study of muscadine grape skin extract in men with biochemically recurrent prostate cancer: safety, tolerability, and dose determination. Prostate. 2015 Oct;75(14):1518-25; Paller CJ, Zhou XC et al. Muscadine grape skin extract (MPX) in men with biochemically recurrent prostate cancer: a randomized, multicenter, placebo-controlled clinical trial. Clinical Cancer Research. 2018 Jan 15;24(2):306-315.

  • Fatigue
  • Gastrointestinal symptoms including flatulence, soft stools, and belching
  • Decreased lymphocyte count
  • Constipation 

High doses of grape seed extract (2500 mg) depressed iron levels among 2 of 29 healthy Japanese adults to lower levels but still within the normal range.2Sano A. Safety assessment of 4-week oral intake of proanthocyanidin-rich grape seed extract in healthy subjects. Food and Chemical Toxicology. 2017 Oct;108(Pt B):519-523.

Interactions with other therapies

Purple grape juice should be avoided for at least 2 hours when taking cyclosporin A, as it can interfere with absorption of cyclosporin A.3Oliveira-Freitas VL, Dalla Costa T, Manfro RC, Cruz LB, Schwartsmann G. Influence of purple grape juice in cyclosporine bioavailability. Journal of Renal Nutrition. 2010 Sep;20(5):309-13.

Keep reading about grapes and grape extracts


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


Andrew Jackson, ND

Research Associate
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Andrew Jackson, ND, serves as a CancerChoices research associate. As a naturopathic physician practicing in Kirkland, Washington, he teaches critical evaluation of the medical literture at Bastyr University in Kenmore, Washington. His great appreciation of scientific inquiry and the scientific process has led him to view research with a critical eye.

Andrew Jackson, ND Research Associate

Last update: June 3, 2024

Last full literature review: February 2024

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.

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