For thousands of years, cocoa have been a very popular food and has been linked to various beneficial health effects. Observational and epidemiological studies point towards a beneficial effect of dark chocolate on cardiovascular morbidity. Several small, albeit controlled studies indeed demonstrate an amelioration of endothelial dysfunction - the dysfunction of the inner layer of the vessels - after intake of dark, flavanol-rich chocolate. This is important, as endothelial dysfunction is an important marker of the development of atherosclerosis and an important prognosticator of future cardiovascular events. This article summarizes the actual literature in this respect.