Flaxseed oil comes from flaxseed (Linum usitatissimum). It is a good source of an essential omega-3 fatty acid called alpha-linolenic acid (ALA).The alpha-linolenic acid and other chemicals in flaxseed oil seem to decrease swelling, which is why some people use it for conditions that involve inflammation, such as rheumatoid arthritis. Flaxseed oil is used for heart disease, high blood pressure, high levels of cholesterol or other fats (lipids) in the blood (hyperlipidemia), and many other conditions, but there is no good scientific evidence to support th