The effects on lipid metabolism of seven combined oral contraceptives were investigated, particularly the effects on high density lipoprotein (HDL) subfractions, which were separated by density gradient ultracentrifugation. There were no differences between the preparations in the effects on the LDL fraction, the so-called atherogenic particle, but there were marked differences in the effects on the anti-atherogenic HDL fraction, of which the effects on HDL-2 were most pronounced. After treatment with monophasic cyproterone acetate and biphasic desogestrel, the cholesterol and phospholipid contents of the HDL-2 fraction were significantly higher than those found after treatment with the other preparations. The lowest values were found after treatment with monophasic levonorgestrel, whereas monophasic desogestrel, triphasic levonorgestrel, monophasic norethisterone and triphasic gestoden induced intermediate values for these variables. The levels of HDL-2 reflect the intrinsic androgenicity of the various progestogens used in the preparations.