Skip navigation
A service of the U.S. National Library of Medicine
From the National Institutes of HealthNational Institutes of Health

Red clover


What is it?

Red clover is a plant. The flower tops are used to make medicine.

Red clover is used for many conditions, but so far, there isn’t enough scientific evidence to determine whether it is effective for any of them. It doesn’t seem to work, though, for lowering cholesterol or controlling hot flashes in women.

Red clover is used for cancer prevention, indigestion, high cholesterol, whooping cough, cough, asthma, bronchitis, and sexually transmitted diseases (STDs).

Some women use red clover for symptoms of menopause such as hot flashes; for breast pain or tenderness (mastalgia); and for premenstrual syndrome (PMS).

Red clover is applied to the skin for skin cancer, skin sores, burns, and chronic skin diseases including eczema and psoriasis.

In foods and beverages, the solid extract of red clover is used as a flavoring ingredient.

Red clover contains hormone-like chemicals called isoflavones that seem to cause reproductive problems in certain animals. Experts think a diet high in isoflavones may have been responsible for reports of reproductive failure and liver disease in cheetahs living in zoos. In large quantities, red clover can cause sterility in livestock.

How effective is it?

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

The effectiveness ratings for RED CLOVER are as follows:

Possibly ineffective for...

  • High cholesterol in women. Research shows that taking red clover extracts by mouth for 3 months to a year does not seem reduce “bad” cholesterol or increase “good” cholesterol in women who have moderately elevated cholesterol levels.
  • Prevention of weak bones (osteoporosis) in women. Research shows that taking a red clover extract for a year does not seem to increase bone strength in women.

Insufficient evidence to rate effectiveness for...

  • Prostate gland symptoms (such as increased nighttime urination) in men. Research suggests that red clover supplements might improve symptoms of benign prostatic hyperplasia (BPH). It seems to decrease nighttime urination and improve the quality of life in men with BPH. But, red clover doesn’t seem to affect urine flow rate, prostatic-specific antigen (PSA) values, or prostate size.
  • Preventing cancer of the lining of the uterus (endometrial cancer). Research to date suggests that taking red clover supplements doesn’t seem to help prevent endometrial cancer.
  • Cyclical breast pain. There is some evidence that red clover might relieve cyclic breast pain and tenderness.
  • Menopause symptoms. There are contradictory research findings about the effects of red clover on symptoms of menopause. Most research shows that taking red clover by mouth for up to a year does not reduce symptoms such as hot flashes or night sweats. Some research shows that a specific red clover product (Promensil, Novogen) might reduce severity of hot flashes, but doesn’t reduce frequency of hot flashes.
    Other research shows that a different form of red clover (MF11RCE, Melbrosin International) might improve symptoms of menopause-related anxiety and depression.
  • Indigestion.
  • Lung problems (cough, bronchitis, asthma).
  • Sexually transmitted diseases (STDs).
  • Premenstrual syndrome (PMS).
  • Skin problems (cancerous growths, burns, eczema, psoriasis).
  • Other conditions.
More evidence is needed to rate red clover for these uses.

How does it work?

Return to top
Red clover contains “isoflavones” which are changed in the body to “phytoestrogens” that are similar to the hormone estrogen.

Are there safety concerns?

Return to top
Red clover is LIKELY SAFE for most people when used in the amounts found in food. It is POSSIBLY SAFE when used in medicinal amounts.

Red clover can cause rash-like reactions, muscle ache, headache, nausea, and vaginal bleeding (spotting) in some women.

There isn’t enough information to rate the safety of red clover when applied to the skin.

Special precautions & warnings:

Pregnancy and breast-feeding: Red clover is LIKELY SAFE when taken by mouth in amounts commonly found in food. But it is LIKELY UNSAFE when taken by mouth in medicinal amounts. Red clover acts like estrogen and might disturb important hormone balances during pregnancy or breast-feeding. Don’t use it.

Not enough is known about the safety of red clover when applied to the skin during pregnancy or breast-feeding. Stay on the safe side and don’t use it.

Bleeding disorders: Red clover might increase the chance of bleeding. Avoid large amounts and use with caution.

Hormone-sensitive conditions such as breast cancer, uterine cancer, ovarian cancer, endometriosis, or uterine fibroids: Red clover might act like estrogen. If you have any condition that might be made worse by exposure to estrogen, don’t use red clover.

Protein S deficiency: People with protein S deficiency have an increased risk of forming blood clots. There is some concern that red clover might increase the risk of clot formation in these people because it has some of the effects of estrogen. Don’t use red clover if you have protein S deficiency.

Surgery: Red clover might slow blood clotting. It might increase the chance of extra bleeding during and after surgery. Stop taking red clover at least 2 weeks before a scheduled surgery.

Are there interactions with medications?

Return to top

Moderate

Be cautious with this combination.

Birth control pills (Contraceptive drugs)
Some birth control pills contain estrogen. Red clover might have some of the same effects as estrogen. But red clover isn't as strong as the estrogen in birth control pills. Taking red clover along with birth control pills might decrease the effectiveness of birth control pills. If you take birth control pills along with red clover, use an additional form of birth control such as a condom.

Some birth control pills include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.

Estrogens
Large amounts of red clover might have some of the same effects as estrogen. But red clover isn't as strong as estrogen pills. Taking red clover along with estrogen pills might decrease the effects of estrogen pills.

Some estrogen pills include conjugated equine estrogens (Premarin), ethinyl estradiol, estradiol, and others.

Medications changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)
Some medications are changed and broken down by the liver. Red clover might decrease how quickly the liver breaks down some medications. Taking red clover along with some medications that are broken down by the liver can increase the effects and side effects of some medications. Before taking red clover, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications that are changed by the liver include amitriptyline (Elavil), haloperidol (Haldol), ondansetron (Zofran), propranolol (Inderal), theophylline (Theo-Dur, others), verapamil (Calan, Isoptin, others), and others.

Medications changed by the liver (Cytochrome P450 2C19 (CYP2C19) substrates)
Some medications are changed and broken down by the liver. Red clover might decrease how quickly the liver breaks down some medications. Taking red clover along with some medications that are broken down by the liver can increase the effects and side effects of some medications. Before taking red clover, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications that are changed by the liver include omeprazole (Prilosec), lansoprazole (Prevacid), and pantoprazole (Protonix); diazepam (Valium); carisoprodol (Soma); nelfinavir (Viracept); and others.

Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates)
Some medications are changed and broken down by the liver. Red clover might decrease how quickly the liver breaks down some medications. Taking red clover along with some medications that are broken down by the liver can increase the effects and side effects of some medications. Before taking red clover, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications that are changed by the liver include diclofenac (Cataflam, Voltaren), ibuprofen (Motrin), meloxicam (Mobic), and piroxicam (Feldene); celecoxib (Celebrex); amitriptyline (Elavil); warfarin (Coumadin); glipizide (Glucotrol); losartan (Cozaar); and others.

Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates)
Some medications are changed and broken down by the liver. Red clover might decrease how quickly the liver breaks down some medications. Taking red clover along with some medications that are broken down by the liver can increase the effects and side effects of some medications. Before taking red clover, talk to your healthcare provider if you are taking any medications that are changed by the liver.

Some medications changed by the liver include lovastatin (Mevacor), ketoconazole (Nizoral), itraconazole (Sporanox), fexofenadine (Allegra), triazolam (Halcion), and many others.

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)
Large amounts of red clover might slow blood clotting. Taking red clover along with medications that also slow clotting might increase the chances of bruising and bleeding.

Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), diclofenac (Voltaren, Cataflam, others), ibuprofen (Advil, Motrin, others), naproxen (Anaprox, Naprosyn, others), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, warfarin (Coumadin), and others.

Tamoxifen (Nolvadex)
Some types of cancer are affected by hormones in the body. Estrogen-sensitive cancers are cancers that are affected by estrogen levels in the body. Tamoxifen (Nolvadex) is used to help treat and prevent these types of cancer. Red clover seems to also affect estrogen levels in the body. By affecting estrogen in the body, red clover might decrease the effectiveness of tamoxifen (Nolvadex). Do not take red clover if you are taking tamoxifen (Nolvadex).

Are there interactions with herbs and supplements?

Return to top
Herbs and supplements that might slow blood clotting
Red clover might slow blood clotting. Using red clover along with other herbs and supplements that can slow clotting could increase the chances of bleeding and bruising in some people. Some of these herbs include angelica, clove, danshen, garlic, ginger, ginkgo, Panax ginseng, horse chestnut, turmeric, and others.

Herbs with estrogenic activity
Large amounts of red clover might have some of the same effects as estrogen. Using red clover along with other herbs that also have some of the effects of estrogen might raise or lower the estrogen-like activity of these other herbs. These herbs include alfalfa, black cohosh, chasteberry, flaxseed, hops, ipriflavone, kudzu, licorice, and soy.

Are there interactions with foods?

Return to top
There are no known interactions with foods.

What dose is used?

Return to top
The appropriate dose of red clover depends on several factors such as the user’s age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for red clover. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

Other names

Return to top
Beebread, Clovone, Cow Clover, Daidzein, Genistein, Isoflavone, Meadow Clover, Miel des Prés, Phytoestrogen, Purple Clover, Trebol Rojo, Trèfle Commun, Trèfle des Prés, Trèfle Pourpre, Trèfle Rouge, Trèfle Rougeâtre, Trèfle Violet, Trefoil, Trifolium, Trifolium pratense, Wild Clover.

Methodology

Return to top
To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.methodology (http://www.nlm.nih.gov/medlineplus/druginfo/natural/methodology.html).

References

Return to top
To see all references for the Red clover page, please go to http://www.nlm.nih.gov/medlineplus/druginfo/natural/308.html.

  1. Lipovac M, Chedraui P, Gruenhut C, et al. Improvement of postmenopausal depressive and anxiety symptoms after treatment with isoflavones derived from red clover extracts. Maturitas 2010;65:258-61.
  2. Geller SE, Shulman LP, van Breemen RB, et al. Safety and efficacy of black cohosh and red clover for the management of vasomotor symptoms: a randomized controlled trial. Menopause 2009;16:1156-66.
  3. Krebs EE, Ensrud KE, MacDonald R, Wilt TJ. Phytoestrogens for treatment of menopausal symptoms: a systematic review. Obstet Gynecol 2004;104:824-36.
  4. Nelson HD, Vesco KK, Haney E, et al. Nonhormonal therapies for menopausal hot flashes: systematic review and meta-analysis. JAMA 2006;295:2057-71.
  5. Cheong JL, Bucknall R. Retinal vein thrombosis associated with a herbal phytoestrogen preparation in a susceptible patient. Postgrad Med J 2005;81:266-7.
  6. Atkinson C, Warren RM, Sala E, et al. Red clover-derived isoflavones and mammographic breast density: a double-blind, randomized, placebo-controlled trial [ISRCTN42940165]. Breast Cancer Res 2004;6:R170-R179.
  7. Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;18:2273-81.
  8. Keinan-Boker L, van Der Schouw YT, Grobbee DE, Peters PH. Dietary phytoestrogens and breast cancer risk. Am J Clin Nutr 2004;79:282-8.
  9. Risbridger GP, Wang H, Frydenberg M, Husband A. The in vivo effect of red clover diet on ventral prostate growth in adult male mice. Reprod Fertil Dev 2001;13:325-9.
  10. Jarred RA, McPherson SJ, Jones ME, et al. Anti-androgenic action by red clover-derived dietary isoflavones reduces non-malignant prostate enlargement in aromatase knockout (ArKo) mice. Prostate 2003;56:54-64.
  1. Geller J, Sionit L, Partido C, et al. Genistein inhibits the growth of human-patient BPH and prostate cancer in histoculture. Prostate 1998;34:75-9.
  2. Hale GE, Hughes CL, Robboy SJ, et al. A doubleblind randomized study on the effects of red clover isoflavones on the endometrium. Menopause 2001;8:338-46.
  3. Atkinson C, Oosthuizen W, Scollen S, et al. Modest protective effects of isoflavones from a red clover-derived dietary supplement on cardiovascular disease risk factors in perimenopausal women, and evidence of an interaction with ApoE genotype in 49-65 year-old women. J Nutr 2004;134:1759-64.
  4. Roberts DW, Doerge DR, Churchwell MI, et al. Inhibition of extrahepatic human cytochromes P450 1A1 and 1B1 by metabolism of isoflavones found in Trifolium pratense (red clover). J Agric Food Chem 2004;52:6623-32.
  5. Schult TM, Ensrud KE, Blackwell T, et al. Effect of isoflavones on lipids and bone turnover markers in menopausal women. Maturitas 2004;48:209-18.
  6. Tice JA, Ettinger B, Ensrud K, et al. Phytoestrogen supplements for the treatment of hot flashes: the Isoflavone Clover Extract (ICE) study: a randomized controlled trial. JAMA 2003;290:207-14.
  7. Puschner B, Galey FD, Holstege DM, et al. Sweet clover poisoning in dairy cattle in California. J Am Vet Med Assoc 1998;212:857-9.
  8. Knight DC, Howes JB, Eden JA. The effect of Promensil, an isoflavone extract, on menopausal symptoms. Climacteric 1999;2:79-84.
  9. Baber RJ, Templeman C, Morton T, et al. Randomized placebo-controlled trial of an isoflavone supplement and menopausal symptoms in women. Climacteric 1999;2:85-92.
  10. Horn-Ross PL, John EM, Canchola AJ, et al. Phytoestrogen intake and endometrial cancer risk. J Natl Cancer Inst 2003;95:1158-64.
  11. Nelsen J, Barrette E, Tsouronix C, et al. Red clover (Trifolium pratense) monograph: A clinical decision support tool. J Herb Pharmacother 2002;2:49-72.
  12. Ingram DM, Hickling C, West L, et al. A double-blind randomized controlled trial of isoflavones in the treatment of cyclical mastalgia. The Breast 2002;11:170-4.
  13. Anon. The role of isoflavones in menopausal health: consensus opinion of the North American Menopause Society. Menopause 2000;7:215-29.
  14. van de Weijer P, Barentsen R. Isoflavones from red clover (Promensil) significantly reduce menopausal hot flush symptoms compared with placebo. Maturitas 2002;42:187-93.
  15. Tice J, Cummings SR, Ettinger B, et al. Few adverse effects of two red clover extracts rich in phytoestrogens: a multicenter, placebo-controlled trial. Alt Ther 2001;7:S33.
  16. Howes J, Waring M, Huang L, Howes LG. Long-term pharmacokinetics of an extract of isoflavones from red clover (Trifolium pratense). J Altern Complement Med 2002;8:135-42.
  17. This P, De La Rochefordiere A, Clough K, et al. Phytoestrogens after breast cancer. Endocr Relat Cancer 2001;8:129-34.
  18. Vincent A, Fitzpatrick LA. Soy isoflavones: are they useful in menopause? Mayo Clin Proc 2000;75:1174-84.
  19. Budzinski JW, Foster BC, Vandenhoek S, Arnason JT. An in vitro evaluation of human cytochrome P450 3A4 inhibition by selected commercial herbal extracts and tinctures. Phytomedicine 2000;7:273-82.
  20. Gerber G, Lowe FC, Spigelman S. The use of a standardized extract of red clover isoflavones for the alleviation of BPH symptoms. Endocrine Soc 82nd Ann Mtg, Toronto, CAN 2000;Jun 21-4:abstract 2359.
  21. Atkinson C, Compston JE, Day NE, et al. The effects of phytoestrogen isoflavones on bone density in women: a double-blind, randomized, placebo-controlled trial. Am J Clin Nutr 2004;79:326-33.
  22. Lissin LW, Cooke JP. Phytoestrogens and cardiovascular health. J Am Coll Cardiol 2000;35:1403-10.
  23. Setchell KD, Cassidy A. Dietary isoflavones: biological effects and relevance to human health. J Nutr 1999;129:758S-67S.
  24. Electronic Code of Federal Regulations. Title 21. Part 182 -- Substances Generally Recognized As Safe. Available at: http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid= 786bafc6f6343634fbf79fcdca7061e1&rgn=div5&view= text&node=21:3.0.1.1.13&idno=21
  25. Kurzer MS, Xu X. Dietary phytoestrogens. Annu Rev Nutr 1997;17:353-81.
  26. Cassady JM, Zennie TM, Chae YH, et al. Use of a mammalian cell culture benzo(a)pyrene metabolism assay for the detection of potential anticarcinogens from natural products: inhibition of metabolism by biochanin A, an isoflavone from Trifolium pratense L. Cancer Res 1988;48:6257-61.
  27. Le Bail JC, Champavier Y, Chulia AJ, Habrioux G. Effects of phytoestrogens on aromatase, 3beta and 17beta-hydroxysteroid dehydrogenase activities and human breast cancer cells. Life Sci 2000;66:1281-91.
  28. Yanagihara K, Ito A, Toge T, Numoto M. Antiproliferative effects of isoflavones on human cancer cell lines established from the gastrointestinal tract. Cancer Res 1993;53:5815-21.
  29. Hodgson JM, Puddey IB, Beilin LJ, et al. Supplementation with isoflavonoid phytoestrogens does not alter serum lipid concentrations: a randomized controlled trial in humans. J Nutr 1998;128:728-32.
  30. Setchell KD, Gosselin SJ, Welsh MB, et al. Dietary estrogens--a probable cause of infertility and liver disease in captive cheetahs. Gastroenterol 1987;93:225-33.
  31. Hargreaves DF, Potten CS, Harding C, et al. Two-week dietary soy supplementation has an estrogenic effect on normal premenopausal breast. J Clin Endocrinol Metab 1999;84:4017-24.
  32. Anthony MS. Soy and cardiovascular disease: Cholesterol lowering and beyond. J Nutr 2000;130:662S-3S.
  33. Ginsburg J, Prelevic GM. Lack of significant hormonal effects and controlled trials of phyto-oestrogens. Lancet 2000;355:163-4.
  34. Duncan AM, Underhill KE, Xu X, et al. Modest hormonal effects of soy isoflavones in postmenopausal women. J Clin Endocrinol Metab 1999;84:3479-84.
  35. Baird DD, Umbach DM, Lansdell L, et al. Dietary intervention study to assess estrogenicity of dietary soy among postmenopausal women. J Clin Endocrinol Metab 1995;80:1685-90.
  36. Barnes S, Kim H, Darley-Usmar V, et al. Beyond ERalpha and ERbeta: Estrogen receptor binding is only part of the isoflavone story. J Nutr 2000;130:656S-7S.
  37. Setchell KD. Absorption and metabolism of soy isoflavones-from food to dietary supplements and adults to infants. J Nutr 2000;130:654S-5S.
  38. Zand RS, Jenkins DJ, Diamandis EP. Steroid hormone activity of flavonoids and related compounds. Breast Cancer Res Treat 2000;62:35-49.
  39. Umland EM, Cauffield JS, Kirk JK, et al. Phytoestrogens as therapeutic alternatives to traditional hormone replacement in postmenopausal women. Pharmacotherapy 2000;20:981-90.
  40. Howes JB, Sullivan D, Lai N, et al. The effects of dietary supplementation with isoflavones from red clover on the lipoprotein profiles of postmenopausal women with mild to moderate hypercholesterolemia. Atherosclerosis 2000;152:143-7.
  41. Nestel PJ, Pomeroy S, Kay S, et al. Isoflavones from red clover improve systemic arterial compliance but not plasma lipids in menopausal women. J Clin Endocrinol Metab 1999;84:895-8.
Show more references
Show fewer references
Last reviewed - 07/18/2011

Browse Herbs & Supplements



Page last updated: 27 September 2012