The Polygoni Radix and Cynanchi Radix have been used to potentiate the liver functions in clinic of Oriental Medicine. The water extracts of Polygoni Radix and Cynanchi Radix were administered orally to rats intoxicated with carbon tetrachloride and then this experiment have been performed by observing liver fatty degeneration and activities of enzymes such as cytochrome oxidase (CYO), adenosine triphosphatase (ATP), acid phosphatase (ACP), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP). By oral administration of water extracts of the radices between 1 and 10 days, the following results were obtained. 1. The group given Cynanchi Radix extract showed recovery of the fat liver in 4 days, whereas that given Polygoni Radix extract did the recovery in 8 days. 2. In cytochrome oxidase activity, the group given Cynanchi extract showed normal activity in 6 days, whereas that given Polygoni Radix extract did the activity in 8 days. 3. In adenosine triphosphatase activity, the groups given Cynanchi Radix and Polygoni Radix extracts showed normal activities in 2 and 8 days, respectively. 4. In acid phosphatase activity, the groups given Cynanchi Radix and Polygoni Radix extracts showed recovery of the activities in 2 and 4 days, respectively. 5. In lactate dehydrogenase activity, the group given Cynanchi Radix and Polygoni Radix extracts showed recovery of the activities in 6 and 10 days, respectively. 6. In alkaline phosphatase activity, the group given Cynanchi Radix extract showed normal activity in 2 days, whereas that given Polygoni Radix extract showed slight recovery between 4 and 6 days followed by decrease of the activity in 8 and 10 days. From the above-mentioned results, it was found that both of the water extracts of Polygoni and Cynanchi Radix possessed the recovery action of liver function as intoxicated with carbon tetrachloride in rats. It is also noted that the extract of Cynanchi Radix showed more potent activity than that of Polygoni Radix.