The acute effects of coffee, cigarette smoking and alcohol on serum lipids, lipoproteins and thromboxane B2 production by platelets were studied in nine healthy volunteers who were non-drinkers of coffee and alcohol and non-smokers. They received, in a single administration, coffee (containing 200 mg of caffeine), alcohol (0.50 ml/kg body wt), or smoked two cigarettes. No differences were observed between baseline and 15, 60 and 80 min values for plasma cholesterol, triglycerides, HDL cholesterol, plasma apolipoproteins A-I and B and thromboxane B2 production. Chronic coffee consumption also did not affect either plasma lipoprotein profile or the interaction of low density lipoproteins with cellular receptors in a group of healthy individuals. These results suggest that coffee itself does not affect acutely the plasma lipoprotein profile in healthy man. This was also true in heavy coffee drinkers.