In a multicentric placebo-controlled randomised study the effect of standardized garlic-powder tablets (Kwai, Sapec) in the treatment of hyperlipidaemia was investigated. A total of 261 patients of 30 general practitioners in West Germany with total cholesterol and/or triglyceride values more than 200 mg/dl (mostly hyperlipoproteinaemia type II a/II b) took part in the study. Patients were randomly allocated to take tablets containing a total of 800 mg garlic powder (standardized to 1.3% of alliin content) daily or the same number of placebo tablets for 16 weeks (monthly controlled). 221 patients were used for statistical analysis of total cholesterol and 219 patients for the analysis of triglyceride values. Mean serum cholesterol levels dropped in the verum group from 266 to 235 mg/dl (i.e. 12%) during the 4 month treatment period, mean triglyceride values fell in the verum group from 226 to 188 mg/dl (i.e. 17%). The best cholesterol lowering effects were seen in the patients with initial total cholesterol values between 250-300 mg/dl. The difference between the verum and placebo group was highly significant (p less than 0.001). A mild garlic smell was observed in up to 21% of the verum group and up to 9% in the placebo group. Only one of the patients left the study for this reason. Standardized garlic tablets have been shown to be effective in the treatment of hyperlipidaemia by lowering total cholesterol values by an average of 12% and triglyceride values by an average of 17%.