Evening primrose is native to North America where it was used for both food and medicine. Native Americans boiled and ate the peppery, 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 planted for food.

Today, evening primrose is mostly grown for its seed oil. The oil, usually called EPO, is used in England to relieve the itchiness of atopic dermatitis, and to ease breast pain and tenderness associated with premenstrual syndrome and other causes. But further research may show its usefulness to extend beyond the treatment of these conditions. Eczema, diabetes, cardiovascular disease, high cholesterol, chronic fatigue syndrome, and even cancer may one day be reasons to use EPO.

Plant Description

A circle of leaves grows close to the ground around evening primrose stems after the first year it is planted. In the second year, flowers grow. The flowers bloom with creamy yellow or bright yellow blossoms from June to September, but only after sunset or on cloudy days.

What's It Made Of?

Using a chemical called hexane, oil is taken from the seeds and prepared as medicine. The seeds contain essential fatty acids, or EFAs, which are a necessary part of our diets. The EFAs in evening primrose seeds are linoleic acid (LA) and gamma-linolenic acid (GLA). Because GLA is known to affect systems in the body that cause or reduce inflammation, it may have a major role in treating many illnesses, especially those that cause pain and inflammation.

Available Forms

You can get EPO as an oil or in capsules. Usually the capsules are preferred. Keep the product out of direct sunlight—better yet, in the refrigerator, which will prevent the oil from becoming rancid.

EPO is usually standardized to an 8 percent gamma-linolenic acid.

How to Take It

Many drugs, such as aspirin, have similar anti-inflammatory and pain relieving effects as EPO. However, these drugs do not supply any kind of dietary fatty acid and they can have side effects. In contrast, EPO gives your body something it may need, with little or no side effects.

If you and your health care provider have decided to try EPO, make sure you keep track of your dosages as well as how the treatment is working for you. Stick with the program that you and your provider have chosen for at least three months. In clinical studies, it has taken that long for effects to be seen, and in many cases, the effects were significant. For example, 60 percent of rheumatoid arthritis patients who took EPO were able to stop or reduce the amount of pain killers they normally took.

Skin rash, mastalgia (breast pain), and premenstrual syndrome (PMS) are the three conditions for which dosages have been recommended. For skin rash, the recommended daily dosage is 6 to 8 g for adults and 2 to 4 g for children. For mastalgia, the recommended dosage is 3 to 4 g daily. For PMS, the recommended dosage is 3 g daily. EPO is available as capsules and as oil. Follow package directions and your health care provider's instructions.

If you are taking EPO for arthritis, dry and scaly skin, or most other conditions, a dosage of about 3 g per day is considered safe. Be sure to discuss this with your health care provider before taking EPO.

Precautions

The American Herbal Products Association (AHPA) gives EPO a class 1 safety rating, which means it's safe with appropriate use. There have been rare reports of nausea and headaches from using it. Stomach pain and loose stools may be indications that your dosage is too high. Talk to your health care provider about it, and lower your dosage based on his/her instructions.

Taking EPO while breastfeeding is believed to be safe. Breast milk actually contains both LA and GLA, and it may be a necessary part of a newborn's diet. Safety during pregnancy has not been determined—talk with your health care provider.

Possible Interactions

If you are taking psychotherapeutic medications to treat schizophrenia, talk with your health care provider before taking evening primrose oil. It can interact with these medications and increase the risk of seizures. For the same reason, you should avoid taking this herb with antidepressant medications (medicines to treat depression), particularly tricyclic antidepressants, and anticonvulsant medications that are used to treat seizure disorders.

Supporting Research

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Brehler R, Hildebrand A, Luger TA. Clinical reviews: recent developments in the treatment of atopic eczema. J Am Acad Dermatol. 1997; 36: 989–990.

Corbett R, Menez JF, Floch HH, et al. 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.

Foster S. Herbal Renaissance: Growing, Using and Understanding Herbs in the Modern World. Salt Lake City, Utah: Gibbs-Smith; 1993.

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Graham-Brown R. Psychodermatology: Managing adults with atopic dermatitis. Dermatologic Clinics. 1996;14: 536.

Greenfield, S.M. et al. A randomized controlled study of evening primrose oil and fish oil in ulcerative colitis. Aliment Pharmacol Ther. 1993;7:159–166.

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Scarff DH, Lloyd DH. Double-blind, placebo-controlled crossover study of evening primrose oil in the treatment of canine atopy. Veterinary. 1992.

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Stewart JCM, et al. Treatment of severe and moderately severe atopic dermatitis with evening primrose oil (Epogam): a multi-center study. J Nut Med. 1991;2:9–16.

Copyright © 2000 Integrative Medicine Communications

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