In order to study antioxidative acton of garlic, alliin, scordinin, garlic oil, ethanol fraction and non-kaolin fraction which have been discovered from garlic until now were extracted and isolated, and each fraction was utilized as the experimental materials. Antioxidative action of each fraction was compared through the in vitro and in vivo experiments. Electron donatingability on $alpha$, $alpha$-diphenyl-$eta$picrylhydra-$chi$yl, the inhibitory effect of lipoperoxide formation by TBA and peroxide value were measured and analyzed. RESULTS : 1. When observed antioxidative ability by EDA value, ethanol fraction of garlic components showed the strongest reaction as 15.25. 2. In vitro experiment with TBA value, garlic oil, alliin and ethanol fracton showed distinctive effect on inhibitory effect of lipoperoxide formation. 3. Comparing with the inhibitory effect of lipoperoxide formation with TBA value in vivo, the ethanol fraction was the most effective in the blood or liver by intraperitoneal administration, whereas the ethanol fraction in the blood and non-kaolin fraction in the liver was most effective each other by orally administration. 4. In vitro experiment with peroxide value, garlic oil was distinctive effect on the inhivitory effect of lipoperoxide formation, which was a similar to the trend of TBA value in vitro. 5. Examining the induction time for the first period of lipoperoxide formation in vitro, garlix oil, ethanol fraction and alliin were effective, which was a similar to the trend of TBA value and peroxide value in vitro.