Our earlier studies have shown that heavy alcohol intake increases the serum concentration of HDL2. The present study aimed to test which HDL subfraction is affected by moderate alcohol intake, and to examine the time- and dose-dependency of alcohol-induced changes in serum lipoproteins. Therefore, 30 or 60 g day-1 of alcohol were given to 10 healthy male volunteers during two 3-week periods separated by an abstinence period of 3 weeks. Lipoproteins were fractioned by sequential flotation. On both doses the total HDL3 concentrations rose progressively, the maximum increases being 10 and 25% at the end of respective drinking periods. In contrast, the HDL2 increased slightly only on the dose of 60 g day-1. The serum concentrations of apoprotein A-I and A-II increased on both doses but significantly only on the dose of 60 g day-1; the increments being 22 and 35%, respectively. On the basis of these and our earlier findings we conclude that (i) the effects of heavy and moderate alcohol intake on serum HDL-subfractions are different: the former preferentially increases the HDL2 whereas the latter augments the HDL3; (ii) alcohol-induced changes in serum lipoproteins are both time- and dose-dependent.