Population-based studies suggest moderate and regulär consumption of alcoholic beverages and especially of red wine to reduce morbidity and mortality from coronary heart disease. These beverages may interfere with immune acüvation cascades crucial in the pathogenesis of coronary heart diseases. Neopterin concentrations in human body tluids were found to increase in the course of coronary heart disease indicating the activity of the atherogenetic process. In this study, human peripheral blood mononuclear cells (PBMC) stimulated with mitogens phytohaemagglutinin and concanavalin A were exposed to red and white wines, to ethanol and to grape juice as a non-alcoholic control in vitro. Neopterin production and tryptophan dcgradation were mcasured in supcrnalants. Both biochemical effects are induced by Thl-type cytokine interferon-y and allow monitoring of immune actnation. In stimulated PBMC increased production of neopterin and degradation of tryptophan was observcd Red and white wines, as well as grape juice mhibited these stimulation-induced effects, higher concentrations being more cffective. Ethanol had comparably small if any effect, Red and white wines as well as grape juice do\\ nregulate cytokine-mediated effects in PBMC. Most likely, antioxidant ingredients of wine and grape juicc such as resveratrol are capable of interfering with immunologic pathways which appear to be of relevance, e g.. in the pathogenesis of cardiovascular disease.