Evening primrose oil is extracted from the seeds of the plant Evening primrose. It is a rich source of gamma linolenic acid (GLA) which is an omega 6 fatty acid. Evening primrose oil has been traditionally used for arthritis, nerve damage due to diabetes, atopic dermatitis including eczema, and high blood pressure. In particular, it is known to reduce the symptoms of premenstrual syndrome (PMS) such as breast pain, depression, irritability, bloating, or headache. Scientific research is still ongoing to prove these benefits.