Aim: Clinical investigations of the effects of garlic preparations in hypercholesterolemia have demonstrated somewhat controversial results. These discrepancies may be due to the differences of the composition of garlic preparations and the biological response they may induce. The study was undertaken to test the hypothesis that garlic powder tablets with a prolonged mode of action promise potent biological effects. Methods: The lipid-lowering effects of time-released garlic powder tablets, Allicor (600 mg daily), were investigated in a double-blinded placebo-controlled randomized study in 42 men aged 35 − 70 with mild hypercholesterolemia. Results: Allicor treatment resulted in a moderate but statistically significant decrease in total cholesterol level that was observed after 8 and 12 weeks of active treatment. By the end of the study, total cholesterol in Allicor-treated patients had fallen by 7.6% (p 0.004) as compared to the level at randomization, and was 11.5% lower than the placebo group (p 0.005). LDL cholesterol in Allicortreated patients fell by 11.8% (p 0.002) and 13.8% (p 0.009), respectively. HDL cholesterol also increased significantly after 8 and 12 weeks of treatment. By the end of the study, HDL cholesterol in Allicor-treated patients had increased by 11.5% (p 0.013). Conclusion