Abstract: Objective The obvious toxical symptoms and signs, the toxic damage extents and reversibility were observed in rats caused by water extract of Radix et Rhizoma Sophorae Tonkinensise. Methods The 80 rats were divided into four groups such as normal group and water extract of high, medium and low dose. The general conditions including the bodyweight、diet and behavior were observed, the blood routine, the biochemical indicators, organ/bodyweight rate, the important organs such as heart, liver, spleen, lung, kidney, brain and et al, and pathological changes were detected after water extract administrated, and then the changes were observed during the recovery period. Results The Wistar rat’s weight, diet and drinking were decreased; the ALT、AST、ALP were increased; the liver weight and volume ratio was increased after given water extract from Radix et Rhizoma Sophorae Tonkinensise to Wistar rats by intragastric for 27 days. Pathological examination showed different degree of liver pathology tissue damage; There was little affect for routine blood; The damage of liver toxicity in rats show an obvious dosage relationship. And after the convalescence, the partial lesions were irreversible. Conclusion The main chronic toxical damage is the changes of ALT、AST、ALP、BUN、CRE in rats caused by water extract of Radix et Rhizoma Sophorae Tonkinensise, and part of the lesions were irreversible.

Key words: Radix et Rhizoma Sophorae Tonkinensise, water extract, rats, chronic toxicity