Fish oil is a natural source of the omega-3 fatty acids Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA). Omega-3 fatty acids are essential fatty acids, and must therefore be obtained from the diet or through supplementation. They have a vast array of important functions in the body and a large amount of scientific research supports the effective use of omega-3 fatty acids from fish oil in a variety of conditions, including maintaining cardiovascular health.