Fish oil supplements provide benign omega-3 fatty acids, which are beneficial for a wide range of conditions, including heart and circulatory problems, according to WebMD. Fish oil is also used to treat age-related eye conditions and to prevent certain pregnancy complications.
The most important omega-3 fatty acids in fish oil are eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA, explains WebMD. These fatty acids reduce swelling and pain, and prevent the blood from clotting easily, which is why they are widely used in the treatment of vascular diseases. They are also used to treat dyslexia, asthma, obesity and kidney disease.