The aim of this study is to investigate the effects of onion and acanthopanax senticosus on body weight change, serum total cholesterol, HDL cholesterol, LDL cholesterol, triglyceride, free fatty acid, total lipid, phospholipid level, renal and liver function test, and CBC in obese rats and mice. Obese rats induced by high-fat fed are medicated for 7 weeks. Rats are divided into four groups depending on the medication; normal group (general-fat fed and no-medication), control group (high-fat fed and no medication), sample A group (high-fat fed and onion 100% extracted medication), sample B group (high-fat fed and onion 50% & acanthopanax senticosus 50% extracted medication), sample C group (high-fat fed and red onion 50% & acanthopanax senticosus 50% extracted medication). After medication, obesity related index, renal and liver function test, and CBC are analysed. There are significant statistical differences among control group and all experimental groups for the body weight change. There are significant statistical differences among control groups and all experimental groups for the total cholesterol, HDL cholesterol, LDL cholesterol, triglyceride level, free fatty acid, and phospholipid level. These results suggest that medications of onion and acanthopanax senticosus extracted products are effective for the treatment of obesity. Especially, onion 100% extracted product is more effective than the others.