OBJECTIVE To explore the effect of Xuanbai Chengqi Decoction on respiratory and oxygenation functions and the ex-pression levels of serum aquaporin(AQP)1 and AQP5 in patients with severe pneumonia complicated with gastrointestinal dysfunction of lung heat and fu-organ repletion type.METHODS 60 patients with severe pneumonia complicated with gastrointestinal dysfunc-tion of lung heat and fu-organ repletion type were randomly divided into control group and treatment group,with 30 cases each.The control group received standardized Western medicine treatment,and the treatment group was treated with Xuanbai Chengqi Decoction in addition to the control group.Both groups were treated for 7 d.The respiratory rate and oxygenation index,mechanical ventilation u-tilization rate,the clinical score including CURB-65 and CPIS scores,TCM syndrome score,gastrointestinal function indicators inclu-ding intra-abdominal pressure,serum gastrin(GAS)and vasoactive intestinal peptide(VIP),AQP1 and AQP5 levels were compared between the two groups before and after treatment.Ventilation utilization and ICU hospitalization days during treatment were compared between the two groups.RESULTS After treatment,compared with the control group,the respiratory rate,TCM syndrome score and intra-abdominal pressure in the treatment group were decreased significantly(P<0.05,P<0.01);meanwhile,the oxygenation index and the levels of serum GAS,AQP1 and AQP5 were increased significantly(P<0.05,P<0.01).CONCLUSION Xuanbai Chengqi Decoction can significantly improve clinical symptoms such as respiratory and oxygenation functions in patients,and its mechanism may be related to the regulation of AQP1 and AQP5.