Objective:To test two theories from traditional Chinese medicine:exterior -interior relationship between the lung and large intestine and treating from the intestine principle for lung disorders.The influence of intestine-based treatment using Xuan Bai Cheng Qi Tang (XBCQT) on the concentration of three trace elements-copper (Cu),zinc (Zn),and manganese (Mn)-was observed in the tissues of the lung,small intestine,large intestine,and stomach of rats suffering from chronic obstructive pulmonary disease (COPD).Methods:Thirty-five male Wistar rats were divided randomly and equally into five groups:control;model;Fei treatment (A);Chang treatment (B);and Fei-Chang treatment (C).A rat model of COPD was prepared by tracheal injection of lipopolysaccharide plus exposure to cigarette smoke.Treatments with medicinal herbs started day-22 of administration and exposure to cigarette smoke for 7 days.The control group and model group were administered physiologic (0.9％) saline solution via the stomach.After 7 days of intervention,the tissues of the lung,small intestine,large intestine,and stomach were removed.Inductively coupled plasma-atomic emission spectroscopy was used to detect the levels of Cu,Zn,and Mn in those tissues.Results:Compared with the control group,the Cu concentration in the tissues of the small intestine,large intestine,and stomach increased significantly in the model group (P ＜.05);the Mn concentration in the tissues of the lung,large intestine,and stomach increased significantly in the model group (P ＜.05);the Zn concentration in the tissues of the lung and large intestine decreased significantly in the model group (P ＜.05).In comparison of the model group:the Cu concentration in the tissues of the lung and large intestine decreased significantly in the B group (P ＜.05);the Mn concentration in the tissues of the lung,small intestine,and large intestine decreased significantly in the B group (P ＜.05);the Zn concentration in the tissues of the lung,small intestine,and large intestine increased significantly in the B group (P ＜.05).For the A group versus C group comparison,the Zn concentration in the tissues of the small intestine and stomach increased significantly in the latter (P ＜.05).Conclusion:This study showed that treating from the intestine using Xuan Bai Cheng Qi Tang and its modified formulae can regulate the concentration of trace elements in the main organs of COPD rats.This may be one of the mechanisms for intestine-based treatment for COPD.