Abstract: Objective: To investigate the therapeutic effect of penehyclidine hydrochloride on acute exacerbations of chronic obstructive pulmonary disease(COPD).Methods: Forty-five patients with COPD were randomly divided into control group and treatment group.The basic regimens for the two groups were oxygen,antibiotics and aminophylline.The treatment group was given misting inhalation of sodium chloride(4 ml) and penehyclidine hydrochloride(0.5 ml) twice a day in addition to the routine therapy.The pulmonary function and the arterial blood gas were detected 7 days before and after the therapy.Results: There were no significant differences in pulmonary function or arterial gas blood before treatment between the two groups(P>0.05).After the therapy,the pulmonary function and the relevant parameters of arterial blood gas improved significantly in the two groups(P<0.01).The FEV₁,FEV₁/FVC,PaO₂ and PaCO₂ were much higher in the treatment group than in the control group(P<0.01).Conclusions: Inhalation of penehyclidine hydrochloride may efficiently improve the pulmonary function and the arterial blood gas level in patients with acute exacerhations of COPD.