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evening primrose plant

© 2018 Steven Foster

An evening primrose oil monograph

Latin Name: Oenothera biennis

Common Names: evening primrose oil, EPO

This evening primrose monograph provides basic information about evening primrose oil—common names, usefulness and safety, and resources for more information.


Evening Primrose Basics

  • 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.

Evening Primrose in Health Research

  • Many studies in people have evaluated evening primrose oil for eczema, PMS, or breast pain. Smaller numbers of studies have evaluated it for other health conditions.

Evening Primrose Research Summary

  • 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 Safety

  • 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).

Evening Primrose References

  • Bamford JTM, Ray S, Musekiwa A, et al. Oral evening primrose oil and borage oil for eczema. Cochrane Database of Systematic Reviews. 2013;(4):CD004416. Accessed at is external) on April 9, 2015.
  • Evening Primrose Oil. Natural Medicines Web site. Accessed at on April 6, 2015. [Database subscription].
  • Shahidi F, Miraliakbari H. Evening primrose. In: Coates PM, Betz JM, Blackman MR, et al., eds. Encyclopedia of Dietary Supplements. 2nd ed. New York, NY: Informa Healthcare; 2010:256-266.

PubMed Articles About Oenothera biennis

Source: National Center for Biotechnology Information (NCBI)[Internet]. Bethesda (MD): National Library of Medicine (US), National Center for Biotechnology Information; [1988] – [cited 2018 Apr 5]. Available from:

Nia, SS., Safi, F., Shoukrpour, M., Kamali, A., (2020) An investigation into the effect of evening primrose in dilatation of cervix and pain during and after hysterosalpingography.

Hysterosalpingography is one of the essential diagnostic methods for examining women who have difficulty becoming pregnant. This procedure is somehow invasive and is associated with numerous complications such as allergic sensitivity, pain, abdominal cramps and shock. Therefore, this study aimed to investigate the effect of evening primrose on cervical length and pain during and after hysterosalpingography. In this double-blind clinical trial, 66 candidates for hysterosalpingography were randomly divided into two groups. A group received 1000 mg of evening primrose orally for two days prior to hysterosalpingography, while the control group received a placebo drug similar in size to evening primrose three days prior to hysterosalpingography. The pain level was recorded based on the Visual Analogue Scale (VAS), during tenaculum placement but also immediately and four hours after hysterosalpingography. Finally, the data were analyzed using SPSS (version 20). There was a significant difference between the two groups in terms of pain during insertion of speculum and injection of the contrast medium (p <0.05). Less pain was reported in the evening primrose group compared to placebo. There was no significant difference between the two groups in terms of the length and diameter of the cervix (p <0.05). Given the fact that it is a medicinal plant with no complications and can reduce pain during speculum insertion and during contrast medium injection, evening primrose seems to be a good drug for managing pain during hysterosalpingography.