Fish oils have no effect on cardiovascular morbidity and mortality in patients with multiple risk factors or atherosclerotic vascular disease, a large general practice-based study from Italy has found. The Risk and Prevention Study was double-blind and placebo-controlled. A total of 12,513 patients were enrolled who had multiple cardiovascular risk factors or atherosclerotic vascular disease but none had had a myocardial infarction (MI). They were followed up by a network of 860 GPs. Around half, 6,244 patients, were assigned to 1 g/day of n-3 fatty acids (polyunsaturated fatty acid ethyl esters with eicosapentaenoic acid and docosahexaenoic acid content not less than 85%) and 6,269 to placebo. The primary end point was initially a composite that included death, nonfatal MI and nonfatal stroke but was later revised at one year after a blinded assessment showed a very low event rate. The revised primary end point was death from cardiovascular causes or hospital admissions for cardiovascular problems. The median follow-up was five years.