Abstract: 【Objective】 This study was conducted to comprehensively evaluate the safety of Polygonum hydropiper powder and provide a scientific basis for its safe application in clinical practice.【Method】 Acute toxicity tests and sub-chronic toxicity tests were designed for the study.In the acute toxicity test,20 Kunming mice were firstly selected for the preliminary test and randomly divided into 5 groups,with 4 mice in each group and an equal number of males and females.Five different dose groups (1.875,3.75,7.5,15 and 30 g/kg BW) were set.After a single oral gavage administration,the mice were continuously observed for 7 days,and their behavioral changes,weight gain or loss,and abnormal conditions of organs were recorded.If no mice died in the preliminary test,the number of mice in each group was increased to 10 in the formal test,with the same grouping,administration method and observation indicators.If no mice died still in the formal test,the maximum tolerance test was carried out.Another 20 mice were given the maximum tolerated dose of 30 g/kg BW and then observed for 7 days.In the sub-chronic toxicity test,80 SD rats were randomly divided into 4 groups,namely the high-dose (20 g/kg BW),medium-dose (10 g/kg BW) and low-dose (5 g/kg BW) groups of Polygonum hydropiper powder and the blank control group (given an equal volume of purified water),with 20 rats in each group.The drug was continuously administered for 30 days.The behavioral manifestations,poisoning and death status of the rats were observed,their body weights,food intakes and water intakes were recorded,the blood physiological and biochemical indexes were detected,the organs were collected and weighed and the organ coefficients were calculated,and pathological sections were made.【Result】 In the acute toxicity test of mice,no poisoning symptoms or death occurred in the preliminary test,formal test and maximum tolerated dose test.There were no abnormal changes in the internal organs during autopsy,and the median lethal dose (LD₅₀) was greater than 30 g/kg BW.In the sub-chronic toxicity test of rats,there were no poisoning symptoms or death in each dose group.The trend of body weight gain was similar to that of control group,and the body weight gain of male rats was higher than that of female rats.The thymus index of female rats in the high-dose group was significantly lower than that of control group (P＜0.05),while there were no significant differences in the other organ coefficients compared with control group (P＞0.05).Except for certain changes in the percentage of neutrophils (Neu),alanine aminotransferase (ALT) and aspartate aminotransferase (AST) among the blood physiological and biochemical indexes,there were no significant differences in the other indexes (P＞0.05),and all indexes were within the normal range.There were also no obvious pathological changes in the pathological sections of various internal organs.【Conclusion】 Within the dose range set in this study,Polygonum hydropiper powder had no toxic or side effects on Kunming mice and SD rats and had good safety.In the acute toxicity test of mice,the LD₅₀ of Polygonum hydropiper powder was greater than 30 g/kg BW.In the sub-chronic toxicity test of rats,the high-dose of Polygonum hydropiper powder was administered at 20 g/kg BW for 30 consecutive days,and no obvious toxic reactions were observed.

Key words: Polygonum hydropiper powder; acute toxicity; sub-chronic toxicity; mice; rats; safety