Flaxseed oil comes from the seeds of the flax plant (Linum usitatissimum, L.). Flaxseed oil contains both omega-3 and omega-6 fatty acids, which are needed for health. Flaxseed oil contains the essential fatty acid alpha-linolenic acid (ALA), which the body converts into eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the omega-3 fatty acids found in fish oil. Some researchers think that flaxseed oil might have some of the same benefits as fish oil, but the body is not very efficient at converting ALA into EPA and DHA. And the benefits of ALA, EPA, and DHA are not necessarily the same. Omega-3 fatty acids, usually from fish oil, have been shown to reduce inflammation and help prevent certain chronic diseases, such as heart disease and arthritis. Studies are mixed about whether flaxseed oil is useful for the same conditions.