We have recently reported that patients with severe nodular cystic acne have much lower levels of HDL-cholesterol, apolipoprotein A and hepatic lipoprotein lipase than healthy controls or subjects with acne vulgaris. Since isotretinoin is very effective in the treatment of the nodular cystic acne but has been shown to increase blood lipid levels, we decided to compare its clinical effectiveness and its effects on lipid metabolism with those of minocycline in patients with nodular cystic acne. After 20 weeks, the number and mean diameter of the cysts were definitely decreased in both groups, but the improvement was more striking in the isotretinoin-treated group. At the end of the treatment, the HDL-C and hepatic lipoprotein lipase levels in this group were increased toward normal, but not in the minocycline-treated group. Our study showed a significant remission in the acne of patients treated with isotretinoin but not in that of the minocycline-treated patients. Furthermore isotretinoin can also correct the altered lipid metabolism in these patients.