Cholesterol-lowering agents are still used in some countries for the treatment of benign prostatic hyperplasia (BPH). A randomized, double-blind, placebo-controlled urodynamic study, carried out on 53 patients with proven outflow obstruction, has failed to prove that the drug, beta-sitosteryl beta-D-glucoside (WA184), is superior to placebo in the treatment of outflow obstruction due to BPH when administered at a dose of 0.3 mg/day. Possible reasons for this include an insufficient dose and duration of treatment (this drug is known to have a potent effect on cholesterol metabolism in the prostate) and the predominantly stromal pathological changes which characterize BPH and which may be unaffected by such agents.