To investigate the effect of Jianpi Zhidong Decoction on the histamine(HA) and histidine decarboxylase(HDC) expression in the striatum and serum in a Tourette syndrome(TS) rat modelMethods:Twenty-four SD rats were randomly assigned to blank，model，Chinese medicine，and western medicine groups according to a random number table，with six rats in each group.Except for the blank group，all other groups were given IDPN at 250 mg/kg via intraperitoneal injection for 7 days to establish the TS model.The blank and model groups were administered with saline at 15 mL/kg，the Chinese medicine group with Jianpi Zhidong Decoction at 16 g/kg，and the western medicine group with sulpiride at 21 mg/kg，once daily，for 6 weeks.Body weight and behavioral changes of all groups were compared.Enzyme-linked immunosorbent assay(ELISA) was used to measure HA levels in the striatum and serum.Reverse transcription polymerase chain reaction(RT-PCR) was used to detect HDC mRNA expression in the striatum.Western blot and immunohistochemistry were used to assess HDC protein expression in the striatum.Results:There were no significant differences in body weight among the model，Jianpi Zhidong Decoction，and western medicine groups(P>0.05).After 6 weeks of intervention，both the Jianpi Zhidong Decoction and western medicine groups had lower body weight than the model group(P<0.05).Behavioral scores showed no significant differences between the model，Jianpi Zhidong Decoction，and western medicine groups(P>0.05).After 6 weeks of intervention，the Jianpi Zhidong Decoction and western medicine groups had lower scores than the model group(P<0.01).Compared with the blank group，the model group showed lower serum HA levels(P<0.05).However，serum HA levels were higher in the Jianpi Zhidong Decoction group than in the model group(P<0.05)，while the western medicine group showed a non-significant increase(P>0.05).Striatal HA levels were lower in the model group than in the blank group(P<0.05)，but higher in the Jianpi Zhidong Decoction and western medicine groups than in the model group(P<0.01).Striatal HDC mRNA expression was lower in the model group than in the blank group but the difference was not significant(P>0.05).Compared with the model group，the Jianpi Zhidong Decoction and western medicine groups showed the higher striatal HDC mRNA expression，but the difference was not significant(P>0.05).Western blot results indicated that striatal HDC protein expression was lower in the model group than in the blank group(P<0.05)，while it was higher in the Jianpi Zhidong Decoction group than in the model group(P<0.05) and the western medicine group(P>0.05).Immunohistochemistry showed that the IOD value of HDC in the striatum was lower in the model group than in the blank group(P<0.05).Compared with the model group，the IOD value of HDC in the striatum was higher in the Jianpi Zhidong Decoction group(P<0.05) and the western medicine group(P>0.05).Conclusion:Jianpi Zhidong Decoction can increase serum and striatal HA levels and striatal HDC expression in TS rats.