Evening primrose (Oenothera biennis [Latin]), also known as evening star, produces little yellow flowers that bloom for only one night and then wither and die. The seeds for this plant are used to produce evening primrose oil (EPO), an excellent source of the omega-6 essential fatty acid. Evening primrose oil has been proven to be an effective treatment for many skin disorders, and may also help prevent diseases involving the breasts and central nervous system.

The omega-6 essential fatty acid, gamma-linolenic acid (GLA), is believed to be the active ingredient of evening primrose oil. Gamma-linolenic acid is known to help soothe inflammation in the body, and to support the body’s immune system.