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Evening Primrose Oil

Scientific names: Oenothera biennis

Common names: Evening Primrose Oil is also known as evening primroseand common evening primrose.

Efficacy rating:

ÒÒÒ...Positive clinical trials

Safety rating:

...No safety concerns despite wide use.

What is Evening Primrose Oil?

The evening primrose is a large, delicate wildflower native to North America and is not a true primrose. The blooms usually last only 1 evening. Primrose has yellow flowers, and the fruit is a dry pod that contains many small seeds.

What is Evening Primrose Oil used for?

General uses

Evening primrose oil may be effective for treating rheumatoid arthritis and diabetic nerve disorders, but its usefulness is not clear in the treatment of a type of eczema, hot flashes, breast pain, or multiple sclerosis.

What is the dosage of Evening Primrose Oil?

Evening primrose oil has been administered orally in clinical trials at doses between 6 and 8 g/day in adults and 2 and 4 g/day in children. The typical content of gamma-linolenic acid (GLA) in the oil is 8% to 10%.

Is Evening Primrose Oil safe?


Contraindications have not yet been identified.


Safety and effectiveness in pregnancy and lactation is unproven. Following a woman's use of oral and intravaginal evening primrose oil for cervical ripening a week before giving birth, the infant consequently experienced temporary skin spots due to bleeding under the skin. Both linoleic acid and GLA are normally present in breast milk, and it is reasonable to assume that evening primrose oil is safe to use while breast-feeding.


A case report exists of an interaction between evening primrose oil and lopinavir in which lopinavir blood levels were high enough to cause toxicity.

Side Effects

Evening primrose oil was previously suspected to lower the seizure threshold in schizophrenic patients; however, this is now disputed.


No toxicity, promotion of cancer, or birth defects have been reported.


  1. Evening Primrose Oil. Review of Natural Products. Facts & Comparisons [database online]. St. Louis, MO: Wolters Kluwer Health Inc; February 2012.

Copyright © 2009 Wolters Kluwer Health