Cod-liver oil is composed of vitamin A, D, EPA and DHA. Both EPA & DHA are omega-3 fatty acids. These omega-3 fatty acids keep blood triglycerides in check (high triglycerides are generally linked with increased risk of heart diseases) and may inhibit the progression of atherosclerosis. They also have anti-inflammatory activity; as a result they are also helpful in Crohn’s disease and rheumatoid arthritis. It has been also found that omega- 3 fatty acids are needed for prostaglandin formation. Probably as a result of their effect on prostaglandin they are responsible for blood vessel dilation. A double blind trial found that omega- 3 fatty acids helped to treat patient with Raynaud’s disease. It has been also found that EPA & DHA have some preventive role in cancer and prevent cardiac arrhythmia.