From the Manufacturer:
Evening Primrose Oil is derived from the seeds of the North American Evening Primrose plant, a perennial found in North America. Many Native American tribes used the plant as a source of food.
The evening primrose plant contains an essential fatty acid called gamma linolenic acid (GLA). The body does not produce essential fatty acids so the must be ingested through food and supplementation. GLA is rich in PGE1 prostaglandins—these promote healthy skin and overall hormone balance, as well as a healthy cardiovascular system and reduced inflammation in the body.