Objective To study the effect of Bufei Huatan Formula （Herbal formula for reinforcing the lung to dissolve phlegm） on the changes of activity of Na+-K+-ATPase of the rat models with phlegm retention due to lung deficiency. Methods Thirty SD rats were randomized into normal group

model group and treatment group with 10 in each. The models of lung deficiency with phlegm retention were made with cold wind and smoking. The treatment group received Bufei Huatan Formula

the normal group and model group were given normal saline of equal-volume for 14 days. General activities

times of cough induced by the stimulation of concentrated ammonia within 3 minutes

pathological changes in the lung tissues

and changes of activity of Na+-K+-ATPase were observed. Results The times of cough of the model and treatment groups were increased compared to that of the normal group （P<0.05）. The pathological section of the treatment group showed that the goblet cell hyperplasia and glandular hypertrophy of trachea and bronchi were milder than those of the model group. The activity of Na+-K+-ATPase of the model and treatment group was lower than that of the normal group （P<0.05）

but the treatment group was significantly higher than the model group （P<0.05）. Conclusion Bufei Huatan Formula is able to up-regulate the activity of Na+-K+-ATPase of the model rats with phlegm retention due to lung deficiency. The decrease of activity of Na+-K+-ATPase of the alveolar wall basement membrane is possibly one of the important mechanisms inducing the lung deficiency with phlegm retention.