Abstract: 【Objective】 The aim of this study was to determine the toxicity and safety of Polygonum hydropiper L. extract.【Method】 In the acute toxicity test,20 healthy SPF Kunming mice were randomly divided into 6 groups:Control group 0 g/kg BW and five treatment groups with Polygonum hydropiper L. extract at doses of 20,10,5,2.5 and 1.25 g/kg BW.The toxicity and death of the animals were observed for 7 days.In the maximum dose test of acute toxicity test,20 mice were given the drug by equal volume for 3 times within 24 h,and their physiological status,poisoning and death were observed.On the 8th day post treatment,their organs were observed for abnormalities.In the 30-day feeding experiment,80 healthy SPF SD rats were randomly divided into 4 groups:Control group 0 g/kg BW and Polygonum hydropiper L. high,medium and low dose groups (20,10 and 5 g/kg BW) with 20 mice each group (half female and half male).The rats were treated for 30 days.Their weight,food intake and water intake were recorded daily.On the 7th day after drug withdrawal,blood samples were collected for routine blood test and blood biochemistry test,organ index was calculated,and histopathological examination was performed.【Result】 The results showed that no death occurred in all groups in acute toxicity test,and the LD₅₀ of Polygonum hydropiper L. extract was not obtained.The maximum tolerance of Polygonum hydropiper L. extract in mice was 30 g/kg BW,indicating that the Polygonum hydropiper L. extract was safe and had no acute toxicity.In the subchronic toxicity test,although the body weight,water intake,feed intake and organ index of rats in each administration group were different from those of the control group,they were within the normal range.The white blood cell and lymphocyte indexes of the rats in high dose group decreased significantly (P<0.05),and the neutrophils increased significantly (P<0.05).The white blood cell index of the rats in the middle dose group decreased significantly (P<0.05;P<0.01),there was no significant difference among the other groups (P>0.05).Among the blood biochemical indexes,compared with control group,the TG level of rats in high dose group increased significantly (P<0.05),and the levels of BUN,CREA and TBIL decreased significantly (P<0.05).The BUN level of rats in middle dose group decreased significantly (P<0.05).CREA levels increased significantly (P<0.05),ALT and TG levels in low dose group increased significantly (P<0.05),BUN levels decreased significantly (P<0.05),and there was no significant difference between the other groups (P>0.05).Necropsy and pathological examination showed no obvious abnormal changes,indicating that the extract of Polygonum hydropiper L. was safe and had no subchronic toxicity.【Conclusion】 In brief, Polygonum hydropiper L. spp. extract of 5 g/kg BW and below was safe and nontoxic.

Key words: Polygonum hydropiper L. extract; acute toxicity test; sub-chronic toxicity test