Objective:To investigate the effect of Maxing Shigan decoction on citric acid-induced cough in guinea pig.Method: Guinea pigs were randomly divided into six groups such as normal

model

codeine and three Maxing Shigan decoction groups（high-doses

middle-doses and low-doses）.Drugs had been continuously administered for 7 days before citric acid-induced cough model in guinea pig was established.Frequency of cough and latent period were counted with the system of biomechanical parameter collection

which are responsible for cough signal

voice recording and counting.The content of serum H2O2 and catalase were detected using biochemical methods.Result: The frequency of cough（53.6±10.7）

infiltration of inflammatory cells in bronchial submucosa and content of serum H2O2（71.3±18.8） mol·L-1 were increased in model groups.The frequency of cough

infiltration of inflammatory cells in bronchial submucosa and content of serum H2O2 were decreased by Maxing Shigan decoction（P<0.05）.But latent period of cough was only prolonged by high-doses Maxing Shigan decoction（P<0.05）.Conclusion: The citric acid-induced cough model in uinea g pig could be prevented and cured by Maxing Shigan decoction

and the changed H2O2may be one of mechanisms.