Evening primrose has served as both food and medicine at previous times throughout history, often for upset stomach and respiratory infections. Native Americans ate the boiled, nutty-flavored root, and used leaf poultices from the plant for bruises and hemorrhoids. European settlers took the root back to England and Germany, where it was introduced as food and became known as German rampion because it grew as a crawling vine. The plant was also a Shaker medicine, sold commercially.

Today, evening primrose seed oil (EPO) is used primarily to relieve the itchiness associated with certain skin conditions (such as eczema) and to ease breast tenderness from premenstrual syndrome (PMS) or other causes. It is considered to be potentially useful for the treatment of many conditions including:

• Allergies, particularly skin rash or hives
• Eczema, including redness and scaling in addition to itching
• PMS, including mood swings and bloating in addition to breast tenderness
• Arthritis, primarily rheumatoid
• Dry eyes, from, for example, Sjogren's syndrome (a condition with symptoms of dry eyes, dry mouth, and, often, arthritis)
• Peripheral Neuropathy, a nerve condition experienced as numbness, tingling, pain, burning, or lack of sensation in the feet and/or legs, from Diabetes
• Menopausal symptoms. Although EPO has gained some popularity for treating hot flashes, the research to date has not confirmed that GLA or EPO is beneficial for these symptoms. With that said, there are individual women who report improvement; therefore, it may be worthwhile to talk to your doctor about whether it is safe for you to try EPO or another form of GLA supplements to alleviate hot flashes.
• Weight loss, particularly if you have a family history of obesity
• Alcoholism; EPO may help lessen cravings for alcohol and prevent liver damage. More research is needed in this area.

Other conditions for which EPO is currently under scientific investigation and may prove beneficial include breast cancer, heart disease, high cholesterol, attention deficit/hyperactivity disorder, stomach ulcers, and inflammatory bowel disease (such as ulcerative colitis). While some test tube and animal studies seem promising, it is much too early to tell if EPO is helpful or harmful for these conditions.

Another condition for which a proprietary herbal product has gained popularity is cellulite. The product combines EPO with several different herbs including ginkgo, sweet clover, sea-weed, grape seed oil, and lecithin. A recent study of this product, however, found that it is no more effective than placebo in getting rid of cellulite.

The main active ingredient in EPO is an omega-6 fatty acid known as gamma-linolenic acid (GLA). See What's It Made Of? for a brief description of GLA. Also, please see the monograph on the supplement GLA for detailed information about the science supporting the uses mentioned and other potential uses for GLA and EPO.

A circle of leaves grows close to the ground around evening primrose stems after the first year it is planted. Flowers bloom after sunset, June through September, or on overcast days during the second year. Stems are branched, with alternate leaves (which means that the leaves grow on both sides of the stem at alternating levels). This monograph focuses on the seed from which the oil is extracted.

Oil is extracted from the seeds and prepared as medicine using a chemical called hexane. The seeds contain up to 25% essential fatty acids including linoleic acid (LA) and gamma-linolenic acid (GLA). Both LA and GLA belong to the omega-6 family of fatty acids. The vast majority of North Americans get too much omega-6 fatty acid in their diet. There are differences, though, between the different types of omega-6 fatty acids in terms of whether they are healthy or unhealthy. Please see the monograph on the supplement omega-6 fatty acids for a detailed description of these essential fatty acids, including the effects they have on the body and how to balance them in your diet.

Other sources of GLA include borage and black currant oils.

EPO is available as oil or in capsules (the preferred form). EPO products should be kept in the refrigerator and out of direct sunlight to prevent the oil from becoming rancid.

Generally, high-quality oil will be certified as organic by a reputable third party, packaged in light-resistant containers, refrigerated, and marked with a freshness date.

EPO is usually standardized to contain 8% gamma-linolenic acid.

The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, contain active substances that can trigger side effects and that can interact with other herbs, supplements, or medications. For these reasons, herbs should be taken with care, under the supervision of a practitioner knowledgeable in the field of botanical medicine.

Pediatric

For skin rash, the recommended total daily dosage for children is 2 to 4 grams (in capsule form).

Adult

• Skin rash: the recommended daily dosage is 6 to 8 grams for adults.
• Mastalgia (breast pain): the recommended dosage is 3 to 4 grams daily.
• PMS: the recommended dosage is 3 grams daily.
• Arthritis: a dosage of about 3 grams per day is considered safe.

The American Herbal Products Association (AHPA) gives EPO a class 1 safety rating, which indicates that it is safe with appropriate use. Reported side effects are rare and mild, and include nausea, stomach pain, and headache. Stomach pain and loose stools may be indications that the dosage is too high.

Omega-6 supplements, including GLA and EPO, should not be used if you have a seizure disorder because there have been reports of these supplements inducing seizures.

Taking EPO while breastfeeding is considered safe as breast milk actually contains both LA and GLA. Borage oil, and possibly other substances containing GLA, should not be used during pregnancy because they may be harmful to the fetus and induce early labor.

If you are currently being treated with any of the following medications, you should not use EPO without first talking to your healthcare provider.

Ceftazidime, an antibiotic
GLA from EPO or other sources may increase the effectiveness of ceftazidime, an antibiotic in a class known as cephalosporins, against a variety of bacterial infections.

Chemotherapy for cancer
GLA from EPO or other sources may increase the effects of anti-cancer treatments, such as doxorubicin, cisplatin, carboplatin, idarubicin, mitoxantrone, tamoxifen, vincristine, and vinblastine.

Cyclosporine
In animal studies, EPO administered during treatment with cyclosporine, a medication used to suppress immune function after an organ transplant, for example, may protect against kidney damage (a possible side effect of the medication).

Nonsteroidal Anti-inflammatory Drugs (NSAIDs)
Theoretically, use of NSAIDs, such as ibuprofen, together with borage oil or other GLA containing supplements like EPO may counter-act the effects of the supplement. Research in this area is needed to know if this theory is accurate.

Phenothizines for Schizophrenia
Individuals taking a class of medications called phenothiazines (such as chlorpromazine, fluphenazine, perphenazine, promazine, and thioridazine) to treat schizophrenia should not take EPO because it may interact with these medications and increase the risk of seizures.

al-Sabanah OA. Effect of evening primrose oil on gastric ulceration and secretion induced by various ulcerogenic and necrotizing agents in rats. Food Chem Toxicol. 1997;35(8):769-775.

Aman MG, Mitchell EA, Turbott SH. The effects of essential fatty acid supplementation by Efamol in hyperactive children. J Abnorm Child Psychol. 1987;15(1):75-90

Barre DE. Potential of evening primrose, borage, black currant, and fungal oils in human health. Annals of Nutrition & Metabolism. 2001;45(2):47-57.

Baumgaertel A. Alternative and controversial treatments for attention-deficit/hyperactivity disorder. Pediatr Clin of North Am. 1999;46(5):977-992.

Belch JJ, Hill A. Evening primrose oil and borage oil in rheumatologic conditions. Am J Clin Nutr. 2000;71(1 Suppl):352S-356S.

Bendich A. The potential for dietary supplements to reduce premenstrual syndrome (PMS) symptoms. J AM Coll Nutr. 2000;19(1):3-12.

Brown NA, Brown AJ, Harding JJ, Dewar HM. Nutrition supplements and the eye. Eye. 1998; 12(pt. 1):127-133.

Burgess J, Stevens L, Zhang W, Peck L. Long-chain polyunsaturated fatty acids in children with attention-deficit hyperactivity disorder. Am J Clin Nutr. 2000; 71(suppl):327S-330S.

Calder PC, Miles EA. Fatty acids and atopic disease. Pediatr Allergy Immunol. 2000;11 Suppl 13:29-36.

Calder PC, Zurier RB. Polyunsaturated fatty acids and rheumatoid arthritis. Curr Opin Clin Nutr Metab Care. 2001;4(2):115-121.

Corbett R, Menez JF, Flock HH, Leonard BE. The effects of chronic ethanol administration on rat liver and erythrocyte lipid composition: modulatory role of evening primrose oil. Alcohol Alcohol. 1991;26(4);459-464.

Chenoy R, Hussain S, Tayob Y, O'Brien PM, Moss MY, Morse PF. Effect of oral gamolenic acid from evening primrose oil on menopausal flushing. BMJ. 1994;19(308):501-503.

Darlington LG, Stone TW. Antioxidants and fatty acids in the amelioration of rheumatoid arthritis and related disorders. Br J Nutr. 2001;85(3):251-269.

Davies CL, Loizidou M, Cooper AJ, et al. Effect of gamma-linolenic acid on cellular uptake of structurally related anthracyclines in human drug sensitive and multidrug resistant bladder and breast cancer cell lines. Eur J Cancer. 1999;35:1534-1540.

De La Cruz JP, Martin-Romero M, Carmona JA, Villalobos MA, Sanches DC. Effect of evening primrose oil on platelet aggregation in rabbits fed an atherogenic diet. Thromb Res. 1997;87(1):141-149.

De La Cruz JP, Quintero L, Galvez J, Villalobos MA, Sanchez DC. Antioxidant potential of evening primrose oil administration in hyperlipemic rabbits. Life Sciences. 1999;65(5):543-555.

Endres S, Lorenz R, Loeschke K. Lipid treatment of inflammatory bowel disease. Curr Op Clin Nutr Metabol Care. 1999;2:117-120.

Fan YY, Chapkin RS. Importance of dietary gamma-linolenic acid in human health and nutrition. J Nutr. 1998; 128(9): 1411-1414.

Garcia CM, et al. Gamma linolenic acid causes weight loss and lower blood pressure in overweight patients with family history of obesity. Swed J Biol Med. 1986;4:8-11.

Giamarellos-Bourboulis EJ, Grecka P, Dionyssiou-Asteriou A, et al. In vitro interactions of gamma-linolenic acid and arachidonic acid with ceftazidime on multiresistant Pseudomonas aeruginosa. Lipids. 1999;34:S151-152.

Graham-Brown R. Atopic dermatitis: unapproved treatments or indications. Clin Dermatol. 2000;18(2):153-158.

Head RJ, McLennan PL, Raederstorff D, Muggli R, Burnard SL, McMurchie EJ. Prevention of nerve conduction deficit in diabetic rats by polyunsaturated fatty acids. Am J Clin Nutr. 2000;71:386S-392S.

Hederos CA, Berg A. Epogam evening primrose oil treatment in atopic dermatitis and asthma. Arch Dis Child. 1996;75(6):494-497

Horrobin DF. The role of essential fatty acids and prostaglandins in the premenstrual syndrome. J Reprod Med. 1983;28(7):465-468. .

Kankaanpaa P, Nurmela K, Erkkila A, et al. Polyunsaturated fatty acids in maternal diet, breast milk, and serum lipid fattty acids of infants in relation to atopy. Allergy. 2001;56(7):633-638.

Karch SB. The Consumer's Guide to Herbal Medicine. Hauppauge, New York: Advanced Research Press; 1999:86-87.

Kast RE. Borage oil reduction of rheumatoid arthritis activity may be mediated by increased cAMP that suppresses tumor necrosis factor-alpha. Int Immunopharmacol. 2001;1(12):2197-2199.

Keen H, Payan J, AllawiJ, et al. Treatment of diabetic neuropathy with gamma-linolenic acid. The Gamma-Linolenic Acid Multicenter Trial Group. Diabetes Care. 1993;16(1):8-15.

Kenny FS, Pinder SE, Ellis IO et al. Gamma linolenic acid with tamoxifen as primary therapy tn breast cancer. Int J Cancer. 2000;85:643-648.

Leventhal LJ, Boyce EG, Zurier RB. Treatment of rheumatoid arthritis with black currant seed oil. Br J Rheumatol. 1994;33(9):847-852.

Lis-Balchin M. Parallel placebo-controlled clinical study of mixture of herbs sold as a remedy for cellulite [short communication]. Phytotherapy Res. 1999;13:627-629.

Little C, Parsons T. Herbal therapy for treating rheumatoic arthritis. Cochrane Database Syst Rev. 2001;(1):CD002948.

Madhavi N, Das UN. Effect of n-6 and n-3 fatty acids on the survival of vincristine sensitive and resistant human cervical carcinoma cells in vitro. Cancer Lett. 1994;84:31-41.

Manjari V, Das UN. Effect of polyunsaturated fatty acids on dexamethasone-induced gastric mucosal damage. Prostaglandins Leukot Essent Fatty Acids. 2000;62(2):85-96.

McCarty MF. Nutritional modulation of mineralocorticoid and prostaglandin production: potential role in prevention and treatment of gastic pathology. Med Hypotheses. 1983;11(4):381-389,

Menendez JA, del Mar Barbacid M, Montero S, et al. Effects of gamma-linolenic acid and oleic acid on paclitaxel cytotoxicity in human breast cancer cells. Eur J Cancer. 2001;37:402-413.

Miller LG. Herbal medicinals: selected clinical considerations focusing on known or potential drug-herb interactions. Arch Intern Med. 1998;158(20):2200–2211.

Mitchell EA, Aman MG, Turbott SH, Manku M. Clinical characteristics and serum essential fatty acid levels in hyperactive children. Clin Pediatr (Phila). 1987;26:406-411.

Morphake P, Bariety J, Darlametsos J, et al. Alteration of cyclosporine (CsA)-induced nephrotoxicity by gamma linolenic acid (GLA) and eicosapentaenoic acid (EPA) in Wistar rats. Prostaglandins Leukot Essent Fatty Acids 1994;50:29-35.

Morse PF, Horrobin DF, Manku MS, et al. Meta-analysis of placebo-controlled studies of the efficacy of Epogram in the treatment of atopic eczema: relationship between plasma essential fatty changes and treatment response. Br J Dermatol. 1989;121(1):75-90.

Munoz SE, Lopez CB, Valentich MA, Eynard AR. Differential modulation by dietary n-6 or n-9 unsaturated fatty acids on the development of two murine mammary gland tumors having different metastatic capabilities. Cancer Lett. 1998;126:149-155.

Munoz SE, Piegari M, Guzman CA, Eynard AR. Differential effects of dietary Oenothera, Zizyphus mistol, and corn oils, and essential fatty acid deficiency on the progression of a murine mammary gland adenocarcinoma. Nutr. 1999;15(3):208-212.

Plumb JA, Luo W, Kerr DJ. Effect of polyunsaturated fatty acids on the drug sensitivity of human tumour cell lines resistant to either cisplatin or doxorubicin. Br J Cancer. 1993;67:728-733.

Richardson AJ, Puri BK. The potential role of fatty acids in attention-deficit/hyperactivity disorder. Prostaglandins Leukot Essent Fatty Acids. 2000;63(1/2):79-87.

Rotblatt M, Ziment I. Evidence-Based Herbal Medicine. Philadelphia, PA: Hanley & Belfus, Inc; 2002.

Rothman D, DeLuca P, Zurier RB. Botanical lipids: effects on inflammation, immune responses, and rheumatoid arthritis. Semin Arthritis Rheum. 1995;25(2):87-96.

Shils ME, Olson JA, Shike M, Ross AC. Modern Nutrition in Health and Disease. 9th ed. Baltimore, Md: Williams & Wilkins; 1999:88-90, 1347-1348.

Simopoulos AP. Essential fatty acids in health and chronic disease. Am J Clin Nutr. 1999;70(3 suppl):560S-569S.

Stevens LJ, Zentall SS, Abate ML, Kuczek T, Burgess JR. Omega-3 fatty acids in boys with behavior, learning and health problems. Physiol Behav. 1996;59(4/5):915-920.

Stevens LJ, Zentall SS, Deck JL, et al. Essential fatty acid metabolism in boys with attention-deficit hyperactivity disorder. Am J Clin Nutr. 1995;62:761-768.

Stoll BA. Breast cancer and the Western diet: role of fatty acids and antioxidant vitamins. Eur J Cancer. 1998;34(12):1852-1856.

Thompson L, Cockayne A, Spiller RC. Inhibitory effect of polyunsaturated fatty acids on the growth of Helicobacter pylori: a possible explanation of the effect of diet on peptic ulceration. Gut. 1994;35(11):1557-1561.

Tsai W-S, Nagawa H, Kaizaki S, Tsuruo T, Muto T. Inhibitory effects of n-3 polyunsaturated fatty acids on sigmoid colon cancer transformants. J Gastroenterol. 1998;33:206-212.

Wainwright PE. Do essential fatty acids play a role in brain and behavioral development? Neurosci Biobehav Rev. 1992;16(2):193-205.

Wakai K, Okamoto K, Tamakoshi A, Lin Y, Nakayama T, Ohno Y. Seasonal allergic rhinoconjunctivitis and fatty acid intake: a cross-sectional study in Japan. Ann Epidemiol. 2001;11(1):59-64.

Werbach MR. Nutritional Influences on Illness. 3rd ed. Tarzana, Calif: Third Line Press; 1999:67-70, 89-103, 206-207, 358-362, 371, 445, 455, 471, 562-565, 622-623, 657-660, 666-670, 678-683.

Whitaker DK, Cilliers J, de Beer C. Evening primrose oil (Epogam) in the treatment of chronic hand dermatitis: disappointing therapeutic results. Dermatology. 1996;193(2):115-120.

Worm M, Henz BM. Novel unconventional therapeutic approaches to atopic eczema. Dermatology. 2000;201(3):191-195.

Wu D, Meydani M, Leka LS, et al. Effect of dietary supplementation with black currant seed oil in the immune response of healthy elderly subjects. Am J Clin Nutr. 1999;70:536-543.