This randomized, double-blind, placebo-controlled crossover study was performed in 67 patients of both sexes aged 20 to 78 years with moderate hypercholesterolemia to investigate the antilipemic efficacy and tolerability of food supplement policosanol--a mixture of aliphatic primary alcohols from rice (Oryza sp.). After a 8-week run-in period in which patients were placed on therapeutic lifestyle changes, in particular cholesterol-lowering diet, they were randomly assigned to receive policosanol 10 mg capsules or placebo capsules once daily with the evening meal for 8 weeks. During next 8 weeks those receiving policosanol during the first 8 weeks, received placebo and those taking placebo during the first 8 weeks, received policosanol. Total cholesterol (C), LDL-C, HDL-C, HDL2-C, HDL3-C, triglycerides, oxidized LDL, apoproteins A I and B and lipoprotein (a) as well as AST, ALT, GGT, CK, blood glucose and bilirubin were determined before the treatment, after the first part of the study i.e. after the first 8 weeks and at the end of the study, i.e after the second 8 weeks. Policosanol significantly reduced plasma total cholesterol and increased apoprotein A I but did not change plasma triglycerides, HDL-C, HDL2-C, HDL3-C, LDL-C, oxidized LDL, Lp (a) and apoproteinS. It was well tolerated, with no drug-related effects on safety parameters such as serum aminotransferases, blood glucose, bilirubin, and CK, neither did it cause any clinical adverse reactions.