The purpose of this clinical trial is a short course study about effectiveness and side effects of Anethum in combined hyperlipidemic patients. Two hundred and ninety eight older than fifteen years old patients with combined hyperlipidemia (serum total cholesterol >240mg/dl and triglyceride >250mg/dl) were included in this controlled, double blind, randomized clinical trial. Two hundred and three patients (68.1%) completed the two months period of trial. After two weeks of therapeutic lifestyle changes (diet and sports), patients were randomized into five following groups 1. Nicotinic Acid 3g daily 2. Nicotinic Acid 3g daily plus Cholestyramine 12g daily 3. Clofibrate 2g daily 4. Anethum 6 tablets daily and 5. Placebo 3 capsules daily. After two months, there was no significant differences between the changes observed in lipid profile in Anethum and placebo groups. Considering the effect on total cholesterol level, the difference between Anethum group (-5%), the first (-22.1%) and the second group (-17.2%) (P<0.000) the effect on triglyceride level, the difference between Anethum group (-16.3%), the first (-54.8%) and the third group (-38%) (P<0.000) and the effect on HDL-cholesterol level, the difference between Anethum group (+1%) and the first group (+30.8%) (P=0.001) was significant. The least complaints were in Anethum group (16%) and the most in the second group (74%). No changes in other biochemical tests were significantly different between Anethum and placebo groups. According to these results there is no superiority for Anethum in comparison of placebo to improve the lipid profile in combined hyperlipidemic patients for a two-month course. Although the side effects of Anethum are less than other well defined drugs.