An "unhealthy" diet is considered as a main cause of increased atherosclerotic cardiovascular disease in the industrialized countries. There is a substantial interest in the potential cardiovascular protective effects of "nutraceuticals," that is food-derived substances that exert beneficial health effects. The correct understanding of cardiovascular effects of these compounds will have important implications for cardiovascular prevention strategies. Endothelial dysfunction is thought to play an important role in development and progression of atherosclerosis, and the characterization of the endothelial effects of several nutraceuticals may provide important insights into their potential role in cardiovascular prevention. At the same time, the analysis of the endothelial effects of nutraceuticals may also provide valuable insights into mechanisms of why certain nutraceuticals may not be effective in cardiovascular prevention, and it may aid in the identification of food-derived substances that may have detrimental cardiovascular effects. These findings further support the notion that nutraceuticals do need support from large clinical outcome trials with respect to their efficacy and safety profile for cardiovascular prevention, before their widespread use can be recommended. In fact, the term nutraceutical was coined to encourage an extensive and profound research activity in this field, and numerous large-scale clinical outcome trials to examine the effects of nutraceuticals on cardiovascular events have now been performed or are still ongoing. Whereas it is possible that single nutraceuticals may be effective in cardiovascular prevention, this field of research provides also valuable insights into which food components may be particularly important for cardiovascular prevention, to further advice the composition of a particularly healthy diet. The present review summarizes recent studies on the endothelial effects of several nutraceuticals, that have been intensely studied.