Since the first report by Bang and Dyerberg regarding the apparent beneficial effects of a fish oil-enriched diet on the incidence of atherosclerotic heart disease in Greenland eskimos, a considerable number of studies have been performed regarding the effects of omega-3 polyunsaturated fatty acids on the prevention and treatment of a variety of disease states not necessarily related to atherosclerosis. Studies have been performed on healthy volunteers and in patients with hyperlipidaemia, atherosclerotic vascular disease, diabetes, asthma, psoriasis and chronic renal insufficiency, amongst others. Positive effects on platelet activity, lipid profile, blood rheology and blood pressure--all factors which are presumably of importance in the pathogenesis of atherosclerotic disease have been noted in these studies, albeit with a wide range of variability. Some negative effects also appear to exist. However, some general conclusions can be made regarding the effects of a fish oil-enriched diet.