Background: The inverse association between moderate drinking and coronary heart disease mortality is well established. This study was performed to investigate the kinetics of the alcohol-induced increases in apo A-1, HDL cholesterol, and paraoxonase (PON) activity, as well as to study whether the alcohol-induced increases in PON activity differ within different PON polymorphisms, and to investigate whether moderate alcohol consumption has similar effects on the outcome measures in postmenopausal women as in middle-aged men. Methods: In a randomized, diet-controlled, crossover study, 10 middle-aged men and 9 postmenopausal women, all apparently healthy, nonsmoking, and moderate alcohol drinkers, consumed beer or no-alcohol beer (control) with evening dinner during two successive periods of 3 weeks. During the beer period, alcohol intake equaled 40 and 30 g/day for men and women, respectively. The total diet was supplied to the subjects and had essentially the same composition during these 6 weeks. Before each treatment was a 1-week washout period, in which the subjects were not allowed to drink alcoholic beverages. Results: Moderate alcohol consumption significantly increased serum apo A-I level after 5 days (3.7%, p < 0.05); after 10 days, serum HDL cholesterol level was increased (6.8%, p < 0.001), and after 15 days serum PON activity was increased (3.7%, p < 0.05), all compared with no alcohol consumption. Gene polymorphisms did not modulate the alcohol effect on PON. Conclusions: Serum apo A-I, HDL cholesterol, and PON activity were significantly increased during 3 weeks of moderate alcohol consumption as compared with no alcohol consumption. Moreover, the results suggest that there is a sequence in induction of these parameters. After an increase in apo A-I, HDL cholesterol is increased followed by an increase in PON activity. Increased serum HDL cholesterol level and PON activity may be a mechanism of action not only in healthy middle-aged men but also in post-menopausal women, underlying the reduced coronary heart disease risk in moderate drinkers. Chemicals/CAS: Apolipoprotein A-I; Aryldialkylphosphatase, EC 22.214.171.124; Cholesterol, HDL; Esterases, EC 3.1.