Policosanol is a natural mixture of higher aliphatic primary alcohols isolated from sugar cane wax (Saccharum officinarum L.). It has cholesterol-lowering effects demonstrated in experimental models and in patients with type II hypercholesterolemia, with positive pleiotropic properties such as inhibition of platelet aggregation and lipid peroxidation. Policosanol reduced thromboxane A(2) and malondialdehyde (MDA) serum levels in animals and human beings. Because nitric oxide (NO) can be destroyed by oxygen-derived radicals and policosanol possesses an antioxidant effect, the purpose of this study was to determine the putative interaction between policosanol and nitroprusside (an NO-containing substance) on platelet aggregation and arterial blood pressure in rats. The percentage of inhibition of adenosine diphosphate-induced aggregation (preincubation with nitroprusside) was higher in platelet-rich plasma of policosanol-treated animals than in control animals. Pretreatment with single doses of policosanol significantly increased the nitroprusside-induced hypotensive effect.