Objective:To evaluate the local risk factors of traumatic brain injury(TBI)patients developing gastrointestinal(GI)bleeding during the early hospitalization in neurosurgery intensive care unit(NICU).Method:From September 2005 to February 2006,41 patients admitted to NICU and 13 healthy volunteers were involved in our study.Blood samples at 24 hours,2-3 days and 5-7 days were obtained from each patient via arterial line at 8 a.m.to measure the concentrations of serum adrenocorticotropic hormone(ACTH),total cortisol and gastrin.The collected serum was immersed in an ice bath and tested by the Immulite 1000 systems.Data were analyzed by SPSS 11.5.Results:Within 24 hours following TBI,the concentrations of total cortisol,ACTH and gastrin increased proportionally to the severity of injury,especially significant in the experimental group(P＜0.05).The concentrations of ACTH and gastrin were higher in the GI bleeding positive group than in the GI bleeding negative group,(F=1.413,P=0.253)for ACTH and(F=9.371,P=0.006)for gastrin.GI bleeding had a positive correlation with gastrin concentration(r=0.312,P＜0.05)and a negative correlation with serum hemoglobin(Hb)(r=-0.420,P＜0.01).The clinical incidence of GI bleeding was 24.39%(10/41)in the experimental group.Within 24 hours,GI bleeding had a strong correlation with gastrin concentration(OR=26.643,P＜0.05)and hematocrit(Hct)(OR=5.385,P＜0.05).High ACTH concentration(＞100 pg/ml)increased the frequency of GI bleeding.For patients with severe TBI and treated with routine antacids,the incidence of GI bleeding was 40.91%(9/22)and the mortality rate was 20%(2/10).Conclusions:Low Glasgow coma scale scores,low Hb,high concentrations of gastrin and ACTH(＞100 pg/ml)are risk factors and can be predictive values for post-traumatic GI bleeding.Severe TBI patients have high risks of GI bleeding with high mortality.