This study was aimed at examining the effect of chronic cigarette smoking on a venous occlusion test. Two groups of young healthy men, a control group of 20 non-smoking subjects and a group of 21 smoking subjects having an average consumption of 17.6 packages.day-1.years (SD 8.6) were studied. Venous occlusion performed in smokers did not induce a significant measurable release of von Willebrand factor (vWF). The release of tissue-type plasminogen activator (t-PA) was significantly weaker for the smokers than for the control group (P less than 0.02). An inverse correlation was found between the cumulative parameter of tobacco consumption and the measurable amount of t-PA Ag or vWF Ag released during venous occlusion (r' = -0.994 and r' = -0.889). Cigarette smoking is thus associated with disturbances of the biological response to this venous occlusion test.