This study was conducted to investigate hypocholesteroloemic effect of garlic and onion in rats fed basal diet or cholesterol supplemented diets. Thirty Sprague Dawley rats were fed basal diet and 30 rats were fed basal diet plus 0.5% cholesterol, both containing none(control), 3% garlic or 3% onion for 4 weeks. Supplementation of 0.5% cholesterol significantly increased plasma and liver cholesterols(p<0.01) and liver triglyceride(TG) and plasma glucose(p<0.05). Plasma total cholesterol was significantly decreased in both garlic and onion groups compared to control when they were fed cholesterol supplemented diet(p<0.05). Plasm TG wa significantly decreased in onion groups regardless cholesterol supplementation (p<0.05). There were no differences in plasma glucose and HDL-cholesterol and liver total cholesterol and TG among groups in both basal and choleserol supplemented diets. Platelet aggregation was rather increased in onion group but not singnificantly different.