Objective:To study on relation of functional and pathological changes of for chronic renal damage of Caulis Aristolochiane Manshuriensis with dose and lasting time of medication.Methods:60 SD female rats were randomly divided into 4 groups.Experimental group A

B

C were given intragastrically by lg·kg

-1

·d

-1

2g·kg

-1

·d

-1

and 4g·kg

-1

·d

-1

of Mutong Decoction

respectively

and the normal group（group D）by equal volume of potable water

and their blood samples were taken from the caudal vein at the ends of 6th

12th and 14th weeks

and 24h-urinay were taken for determination of indexes of renal functions

and a part of the renal tissue was taken for morphological detection and other renal tissue was homogenazed for determination of relative indexes.Results:The legal dose of pharmacopeia within 3 months did not have harmful effect on renal functions and pathological structures.but while the increase of the dose could induce renal toxity

whieh is related with the dose and lasting time of medication.Conclusion:The renal toxity of Caulis Aristolochiane Manshuriensis is relative.