Evening Primrose Oil (EPO) (Oenothera biennis)
EPO is a source of essential fatty acids (GLA). Studies suggest that EPO taken orally may relieve breast soreness. Improved results in osteoporosis studies when EPO was taken in conjunction with fish oils and calcium. Purported to help a number of conditions, such as eczema, PMS, chronic fatigue, rheumatoid arthritis, and Sjogren's syndrome.
Headaches, nausea, and gastric upset were reported. Pregnant and nursing women should avoid EPO.