Abstract: Objective To observe the preventive and therapeutic effect of early purgative therapy on the gastrointestinal dysfunction in critically ill patients. Methods A total of 74 cases of critically ill patients were randomly divided into early purgative therapy group(group A,n=26),purgative therapy group(group B,n=26) and control group(group C,n=22),all the patients received the routine treatment.Dachengqi decoction was administrated in group B when internal environment stable for 48 hours,and in group A group within 48 hours.APACHEⅡ score,MODS score,gastrointestinal function score,intra-abdominal pressure and ICU mortality before the treatment and 3,7,14 days after the treatment.The data were analyzed by the variance analysis and Chi square test. Results After the treatment,there were 6 patients died in group A,while 13 cases died in group C.Gastrointestinal function score in group Awas decreased when compared with that before treatmenton d7,and more significantly on d14.On d14,the gastrointestinal function score in group C increased,and was higher than that in group A and group B;On d14,APACHEⅡ score of group A was lower than that in group C,MODS score also was lower than that in C group;and the intra-abdominal pressure decreased when compared with that before the treatment and on d3 and d7;The intra-abdominal pressure of group C increased as compared with that before the treatment or 3d and 7d after the treatment,which was significantly higher than that in group A and B,the difference was statistical significance.In group A,the blood potassium on d3 was higher than that in group C,and the blood sodium on d7 was lower than that in group B,and the blood sodium on d14 was lower than that in both group B and C.The difference in blood potassium,sodium and chlorine before and after treatment were not statistically significant between group B and C.Intra-abdominal pressure and gastrointestinal function score was positively correlated with APACHE score,MODS score and ICU mortality. Conclusion The purgative therapy especially early purgative therapy can reduce the intra-abdominal pressure,gastrointestinal function score,severe symptom score and mortality,have preventive and therapeutic effect on the gastrointestinal dysfunction in critically ill patients,and the effect of early purgative therapy is more significant.