Evening primrose is a plant native to North America, but it grows in Europe and parts of the Southern hemisphere as well. It has yellow flowers that bloom in the evening. Evening primrose oil contains the fatty acid gamma-linolenic acid (GLA).
Native Americans used the whole plant for bruises and its roots for hemorrhoids. The leaves were traditionally used for minor wounds, gastrointestinal complaints, and sore throats.
Today, people use evening primrose oil dietary supplements for eczema (a condition involving red, swollen, itchy skin, sometimes caused by allergies), rheumatoid arthritis, premenstrual syndrome (PMS), breast pain, menopause symptoms, and other conditions.
Evening primrose oil is obtained from the seeds of the evening primrose and is usually sold in capsule form.
There’s not enough evidence to support the use of evening primrose oil for any health condition.
According to a comprehensive 2013 evaluation of the evidence, evening primrose oil, taken orally (by mouth), is not helpful for relieving symptoms of eczema.
Most studies of evening primrose oil for PMS have not found it to be helpful.
Studies of evening primrose oil for breast pain have had conflicting results.
A small amount of evidence suggests that evening primrose oil might be helpful for diabetic neuropathy (nerve problems caused by diabetes).
Evening primrose oil is probably safe for most people when taken for short periods of time. There can be mild side effects, such as stomach upset and headache.
The safety of long-term use of evening primrose oil has not been established.
Evening primrose oil may increase the risk of some complications of pregnancy. Talk with your health care provider if you’re considering using evening primrose oil during pregnancy.
Evening primrose oil may increase bleeding in people who are taking the anticoagulant (blood thinning) medication warfarin (Coumadin).