This Study was attempted to investigate the effect of Allium cepa L. (onion) on the activities of GOT and GPT, the levels total lipids, triglyceride, total cholesterol, phospholipid and ${eta}-lipoprotein$ in the serum and the increase ratio of body and liver weight in the experimentally induced hyperlipemic rats. The activities of S-GOT and S-GPT were significantly decreased in dose of onion juice 3 ml and 5 ml/head as compared to the high lipid-diet control group. The levels of total lipids. Triglyceride, total cholesterol and phospholipids were significantly decreased in dose of onion juice 3 ml and 5 ml/head as compared to the control group, respectively. However, the level of ${eta}-lipoprotein$ was significantly decreased in dose of onion juice 3 ml/head. The levels of triglyceride and total cholesterol in the liver were significanatly decreased in dose of onion juice 3 ml/head. Increase ratio of the body and liver weight were significantly decreased in dose of onion juice 3 ml/head. Anti-fatigue activity of onion juice were studied in mice using the swimming performance method. The potencies of anti-fatigue acti-vities was significantly found in 1.2 ml/head. p.o. of onion juice. The methanol extract and juice extract of onion was significantly found to have an antioxidative activity on the air oxidation of linoleic acid as compared to the 3-butyl-4-hydroxyanisole and ${alpha}-tocopherol$.