Moderate regular alcohol intake has been found to be associated with a decreased risk for coronary heart disease and stroke. We investigated the effects of acute intake of red wine (60 g ethanol) and a standard dinner under controlled conditions on haemostatic factors. Shear-induced platelet aggregation (SIPA) decreased after the intake of alcohol irrespective of whether the subjects were fasting or not, and also after the intake of food. The intake of alcohol inhibited the postprandial increase of von Willebrand factor multimers. Plasma levels of plasminogen activator inhibitor 1 activity (PAI-1) and serum triglycerides were increased by alcohol. Excretion of the platelet thromboxane A(2) metabolites 11-dehydrothromboxane B(2) and 2,3-dinorthromboxane B(2), as well as the endothelial prostacyclin metabolite 2, 3-dinor-6-ketoprostaglandin F(1)alpha, into urine was not influenced by either alcohol or food. We conclude that eating a dinner together with red wine has no untoward effect on SIPA and that the decrease of SIPA is not specific for alcohol.