Evening Primrose is a perennial weed. Blooms can be white, yellow or pink. The seeds are used to make evening primrose oil. Evening Primrose oil which contains gamma linolenic acid, lioleic acid and oleic acid. It is the gamma linolenic acid (GLA) that is most helpful as an anti-inflammatory agent.
GLA decreases the production of inflammatory proteins and can help control symptoms of rheumatoid arthritis. It can take 1-3 months before symptoms improve.
Other sources of GLA include borage oil and black currant.