In Order to study antioxidative action of water soluble fractions which had been steamed according to time as 15, 30, 60 and 120 minutes, they were compared through the inhibitory effect of lipoperoxide formation by TBA, peroxide value and induction time for the first period of lipoperoxide formation. Results are obtained as follows: 1. In vivo experiment with TBA value, water soluble fractions showed aninhibitory effect of lipoperoxide formation. 2. Comparing with the inhibitory effect of lipoperoxide formation with TBA value in vivo, water soluble fractions which had been steamed for 30 and 60 minutes and those from fresh garlic proved effective in the blood by intraperitoneal administration. But in the liver all of water soluble fractions showed distinctive effect as in the case of fresh garlic. 3. Effect of water soluble fractions which had been steamed for 15, 30 and 60 minutes showed a distinctive effect, water soluble fraction which had been steamed for 120 minutes and that from fresh garlic also showed effective in the blood as compared with control. 4. In oral administration, water soluble fraction of fresh garlic was the most effective in the liver. 5. In vitro experiment with peroxide value, water soluble fractions which had been steamed for 60 and 120 minutes were effective, all of water soluble fractions from steamed garlic were more effective than fresh garlic. 6. In Examining the induction time for the first period of lipoperoxide formation in vitro, water soluble fractions steamed for 30, 60 and 120 minutes were effective. Other fractions were also more effective than control.