An increase in the uptake of long-chain Omega-3 fatty acids from fish with the diet or as ethyl esters resulted in a decreased risk for cardiac death. As mechanism for this rapidly occurring benefit (within 90 days of treatment significantly different to placebo) antiarrhythmic effects at cardiac myocytes and plaques stabilization can be discussed. The results of the GISSI Prevenzione Trial show that 175 patients have to be treated for one year to avoid one death. Regarding other available data for secondary prevention this efficacy is superior to pravastatin and at the same level as simvastatin or aspirin. Only beta-blocking agents are superior, but it is of interest that long-chain Omega-3 fatty acids from fish display their beneficial effects even in patients already treated with beta-blockers. As the intake of 0.85 g of long-chain Omega-3 fatty acids from fish per day can be regarded as save and the positive effect on total mortality occurs already after 90 days their regular use is a promising additional measure for secondary prevention.