Objective: To observe the toxic reactions and organ injuries in wistar rats induced by modified Zexie Tang

determinate the dose of toxic reactions and provide reference for proposing the safe dosage in human beings. Method: Eighty Wistar rats were randomly divided into normal group and modified Zexie Tang low

middle and high dose groups (15

30

60 g·kg-1)

with 20 rats in each group

half male and half female. Rats were administered ig with this medicine once a day for 90 consecutive days. The animal signs were observed and recorded every day. Animal blood test and serum biochemical test were conducted at the end of administration and two weeks after drug withdrawal. The main organs of rats were weighed

organ index was calculated and histopathological examination was taken. Result: Modified Zexie Tang had no effect on organ index. Rats in high dose group had decreased activity

and their hair became yellow and slipping.Body weight of female rats in middle dose group and low dose group in 9th week and 10th week was significantly lower than that in control group (P<0.01

P<0.05). Body weight of female rats in high dose group in 10th week was significantly lower than that in control group (P<0.05).Histopathological examination showed that edema

necrosis and falling off in renal tubular epithelial cells occurred in 1 male rat and 1 female rat in modified Zexie tang high dose group

and liver congestion occurred in one male rat. Conclusion: No obvious harmful effects were observed in rats of modified Zexie Tang middle dose group after 90 days of medication

but high dose group may have certain liver and kidney injury. Therefore

we shall pay close attention to the risks for liver and kidney toxicity in application of long-term and large dose of modified Zexie Tang.