Evening Primrose: "King's Cure-all"

by Irene Yaychuk-Arabei, PhD, RNC
Reproduced from Health Naturally - March/April 1993

Evening Primrose (onethera biennis) is a biennial herb that has gained recognition in the scientific world - because of its precious seed oil. It has been used for more than 500 years by the Algonquin Indians, both as food and medicine. In the 16th century, knowledge of this plant was passed to the Europeans - who called it "King's cure-all."

This plant was one of the earliest wild edibles transplanted to Europe as a food. The first-year roots were boiled or pickled. The leaves were peeled and eaten raw. The oil was an important ingredient in medicines used to treat burns, wounds and skin lesions. Essential fatty acids (EFAs) were actually discovered in 1929. They are food factors that, like vitamins, cannot be made by the body but must be obtained from foods. In 1978 EFAs were reported to be key ingredients in evening primrose oil. Dr. David Horrobin, of the Clinical Research Institute of Montreal, experimented with Evening Primrose Oil in treating 40 multiple sclerosis patients. Later research has revealed that Evening Primrose Oil is effective for many diseases related to deficiencies of essential fatty acids. EFAs have structural and functional roles in all cell membranes, especially the brain. They are also converted to prostaglandins (PGs) - hormone-like chemicals that are manufactured in each organ as needed and then rapidly destroyed. Through cellular reactions, prostaglandins play a vital role in the second-by-second control of how these organs work. (There are many prostaglandins, both beneficial and harmful. The goal of research is to help the body produce "good" prostaglandins and reduce its production of "bad' prostaglandins.) Cis-linoleic acid, on of the EFAs found in vegetable or seed oils, is converted in the body to gammalinoleic acid (GLA) in order to be utilized. Yet, Dr. Horrobin feels that most people are deficient in the ability to convert linoleic acid into GLA - thereby seriously curtailing the production of one of the most critical prostaglandins, PGE. Diets high in refined foods and processed vegetable oils (containing trans fatty acids) tend to block this conversion. Alcohol further reduces GLA formation. Aging causes a decrease in the ability to make GLA (that may itself be a factor in aging). Diabetes, viral infections, radiation, cancer - as well as nutritional deficiencies of zinc, magnesium, vitamin B-6 (pyridoxine) are all factors affecting conversion. Once GLA is formed, it soon converts to dihomogammalinolenic acid (DGLA) - which can then be converted into other compounds, the most important being PGE1. This PGE1 can stop thrombosis, lower blood pressure, slow down cholesterol production, and enhance the effect of insulin. It also helps to prevent inflammation and control arthritis. Its action on the brain promotes a feeling of well being. Laboratory experiments suggest that PGE1 stops the growth of many types of cancer cells. Acute EFA deficiency in humans was observed in the 1950s. Infants given artificial milk formulations that were far too low in EFA levels developed dry, scaly skin, eczema-like rashes, irritability and a substantial increase in calorie intake. Appetites normalized and the skin cleared rapidly when the EFAs were added to the formula. EFA deficiency became apparent again in the 1970s when fluids for total parenteral nutrition were being developed. The U.S. Food and Drug Administration would not allow EFAs to be included. This resulted in skin rashes resembling psoriasis or eczema, failure of wounds to heal and irritability. Evening primrose seed oil contains significant amounts of gamma-linoleic acid. It is not the only form of GLA, however. Borage oil and black current oil have recently been discovered to exhibit properties similar to primrose oil. The only other food containing significant amounts of this substance is breast milk, which contains over four times the amount found in cow's milk. When switched from breast to bottle, babies often develop eczema due to lack of GLA

Atopic Eczema

It is speculated that certain genetic problems may be the result of faulty prostaglandin metabolism. Atopy, for example, is a genetic maladaption of the immune system. People with this condition are susceptible to eczema, asthma, hay fever, allergies or migraines. Atopic individuals are more likely to suffer reactions to aspirin and other non-steroidal anti-inflammatory drugs. They also fail to flush when niacin compounds are applied to the skin. (The niacin flush is related to the increased synthesis of PGs.)

There is a relationship between cystic fibrosis (CF) and atopy. Children with CF have low levels of linoleic acid metabolites and do not respond to treatment with linoleic rich safflower oil. A lack of the enzyme delta-6-desaturase (D6D), which converts cis linoleic acid to gamma-linoleic acid is evident in CF. This biochemical effect can be bypassed by providing GLA in the form of evening primrose oil. Significant clinical improvement was evident.

Breastfeeding protects infants from the development of atopy - partly because human breast milk is rich in the products of delta-6-desaturase activity, GLA and arachidonic acid. A six month old baby, fully breast-fed, is receiving the equivalent of 3-4 capsules of evening primrose daily.

Atopics are usually susceptible to viral bronchiolitis. Such infections could permanently damage an already defective enzyme system by blocking the delta-6-desaturase, leaving the youngster at risk of having low levels of PG precursors.

Multiple Sclerosis

In multiple sclerosis (MS), fatty layers around the myelin sheath of the nerves are degenerating. There is also evidence of abnormality in the immune function and EFA metabolism. If symptoms of an illness are relieved by the addition of a certain nutrient, then it can be assumed that the body was deficient in that particular substance. This is often apparent with MS - particularly if the disease is supplemented with oil of primrose early in its development. Deterioration usually stops, although the disease itself is not necessarily cured.

Hyperactivity in Children

The Hyperactive Children's Support Group in England observed that many children who are hyperactive are also atopic. One common symptom is continuous thirst yet concentrated urine production, brought about by abnormally permeable skin surfaces that allow increased loss of fluid. The use of evening primrose oil in treating hyperactivity is only successful with children who are both hyperactive and atopic or come from atopic families. Better than 80 percent of these children have shown improvement.

Arthritis and Related Disorders

Evening primrose oil may produce improvement in rheumatoid arthritis. It also may enhance tear production in those with dry eye syndrome or Sjogren's syndrome. EFA deficiency leads to atrophy of lachrymal glands. PGE1 helps regulate tear secretion. Evening primrose oil proved to be the most effective agent in these cases.


Consuming alcohol may induce an artificial mania during which the prostaglandin E levels in the blood are substantially elevated. The hangover stage is similar to the depression phase where prostaglandin E levels crash. While alcohol stimulates PGE1 synthesis, it also depletes DGLA stores. When alcohol wears off, these DGLA stores may still be reduced and PGE1 levels may fall below normal. Chronic alcohol excess may eventually lead to a state of long term functional EFA deficiency. Gamma linoleic acid in the form of evening primrose oil reduces the severity of withdrawal syndrome and hangovers.

Premenstrual Syndrome

Premenstrual syndrome (PMS) plagues many women during the days following ovulation until the onset of menses. Symptoms include weight gain, breast pain, irritability, depression, headaches and a host of other discomforts. Symptoms have been relieved in mild to severe cases with the use of evening primrose oil. Vitamin B-6 (pyridoxine) increases the efficiency with which the body tissues make use of EFAs.

Other Conditions

A South African Medical Journal reported that Evening Primrose Oil may reduce cancer cell growth by up to 70 percent. Studies were conducted on both human and mouse cells. Gamma-linoleic acid was toxic to malignant cells, but not normal cells. Brittle nails, an apparent symptom of EFA deficiency, improve within 3 or 4 weeks of using evening primrose oil. Oil of evening primrose needs other nutrients which help to convert GLA in prostaglandins E. These adjunctive supplements include zinc, vitamin C, vitamin B-3, and B-6.

Safety of Evening Primrose Oil

An excessive intake of Evening Primrose Oil may cause headaches. Reducing the amount of oil consumed and taking capsules with food usually alleviates such discomfort. Softer stools are the frequent result of too much oil. Epileptics should be given this oil cautiously, since the condition of those suffering temporal lobe epilepsy may deteriorate with very high doses, although lower doses (less than twelve capsules daily) have not shown any side effects. A nutritional consultant can help one to choose the most effective program for one's biochemical individuality. For further information contact: Nutritional Consultants Organization of Canada, 1201 Division St., Kingston, ON K7K 6X4 (613) 544-8535.


  1. Erasmus, Udo Fats and Oils, (Alive books, 1986)
  2. Horrobin, David F. Essential Fatty Acids: A Review (Clinical Uses of Essential Fatty Acids, 1982)
  3. Moore, Michael Medicinal Plants of the Mountain West, (The museum of New Mexico Press, 1979)
  4. Irene Yaychuk-Arabei, PhD, MH, RNC is a holistic health educator, with combined expertise in nutrition, herbs, and specialized kinesiology. Much of her knowledge comes not only from intensive study but also from personal experience. She has lectured in Canada, the United States, Europe and Russia. In addition to being a Master Herbalist, Irene is also certified as an instructor in Human Ecology Balancing Sciences and Touch for Health. Irene practises in Brantford, Ontario.