Objective To evaluate the therapeutic effect of Zidan Granules [granules of Zicao（Radix Arnebiae） and Mudanpi（Cortex Moutan）] for kidney damage in children with allergic purpura（AP）.Methods Totally 246 children with AP were randomized into the treatment group and control group

with 124 and 122 in each.The treatment group was given basic treatment and Zidan Granules.The control group was given basic treatment and Zidan Granules placebo.Both groups were treated for 4 weeks.The urine routine

urinary β2 microglobulin

urinary microalbumin and the efficacy of disease and TCM patterns were observed in both groups.Results There were 8 cases（6.45%） and 19 cases（15.57%） occurred kidney damage in the treatment group and control group respectively

with a significant difference between groups（P<0.05）.There was no significant difference between groups in the efficacy of disease and TCM patterns（P>0.05）.The efficacy of disease showed that there were 109 cases（87.90%） cured

15 cases（12.10%） effective and 0 ineffective in the treatment group and there were 102 cases（83.61%） cured

20 cases（16.39%） effective and 0 ineffective in the control group.The efficacy of TCM patterns showed that there were 111 cases（89.52%） cured

8 cases（6.45%） markedly effective

5 cases（4.03%） effective and 0 ineffective in the treatment group and there were 103 cases（84.43%） cured

13 cases（10.66%） markedly effective

6 cases（4.91%） effective and 0 ineffective in the control group.Conclusion Zidan Granules can reduce the occurrence of kidney damage in children with AP.