OBJECTIVE: To study the effect of oxymatrine (Oxy) on airway inflammation and the distribution of dendritic cells (DC) in lung and spleen tissues of asthmatic mice. METHODS: Fifty BALB/c mice were assigned into five groups (n=10): an asthma model group, a dexamethasone (Dex) treatment group and three Oxy treatment groups (Oxy dose: 20, 40 and 80 mg/kg respectively). The histological changes of lung tissues were observed by hematoxylin and eosin staining. The expression of 33D1 antigen (a marker of DC) in lung and spleen tissues were detected by immunohistochemical staining. RESULTS: The inflammatory reactions of the lung tissues in the Dex or Oxy treatment groups were less severe than those in the asthma model group. 33D1 antigen was remarkably expressed in the lung and spleen tissues of the asthma model group. After Dex treatment, the expression of 33D1 antigen in the lung and spleen tissues decreased significantly (P<0.01). 33D1 antigen expression in the lung tissues was significantly reduced in all of the three Oxy treatment groups in a dose-dependent manner compared with that in the asthma model group (P<0.01). The treatment with Oxy of 40 and 80 mg/kg decreased significantly the 33D1 antigen expression in the spleen tissues (P<0.01). CONCLUSIONS: Oxy can alleviate airway inflammation and reduce the number of DC in lung and spleen tissues of asthma mice, which may be contributed to the mechanism of Oxy for treatment of asthma.