This randomized, double-blind, placebo-controlled study was conducted in 22 patients with type II primary hypercholesterolaemia to investigate the efficacy, safety and tolerability of two successive dose increases of policosanol. Patients with elevated serum low-density-lipoprotein cholesterol (LDL-C) and total cholesterol after a diet-only period received randomly, under double-blind conditions, placebo or policosanol at 5 mg once-a-day for 8 weeks. After this period, dosage was doubled to 5 mg twice-a-day for the next 8 weeks and then again doubled to 10 mg twice-a-day. It was found that the LDL-C was reduced significantly by 11.3%, 21.9% and 31.2%, while total cholesterol was also reduced significantly by 8%, 14.1% and 23% respectively in these three periods. Serum high-density-lipoprotein cholesterol (HDL-C) was increased by 7.8%, 7.2% and 8.7%, respectively, while in the placebo group a downward shift was observed. The LDL-C to HDL-C ratio was reduced significantly by 15.3%, 25.6% and 34.6%, while the total cholesterol to HDL-C ratio was also reduced significantly by 12.5%, 18.4% and 27.1%, respectively. Triglycerides and VLDL-C values did not change significantly. The reduction of LDL-C, total cholesterol, LDL-C to HDL-C, and total cholesterol to HDL-C ratios showed a dependence on the successive dose increases. Policosanol was very well tolerated. No patient discontinued the trial. No disturbances of clinical or blood biochemistry variables attributable to treatment were observed. Adverse effects reported were mild and transient, and no significant differences between groups were found.