Objective To investigate the effect and clinical significance of 3 d and 1 d bowel preparation method for colorectal carcinoma surgery on preoperative gut mucosal barrier function. Methods Plasma levels of D-lactate (D-LAC), diamine oxidase (DAO) and endotoxin (ET) were measured at 2 h before operation in 3 d bowel preparation group (50 cases) and 1 d bowel preparation group (50 cases), 25 cases of inguinal hernia were included as control group. D-LAC, DAO and ET were detected by using enzymatic spectrophotometric assay, spectrophotometric assay and limulus lysate test with azo chromogenic substrate, respectively. Results Preoperative plasma levels of D-LAC, DAO and ET in 3 d bowel preparation group were (10.25±1.43) mg/L, (5.82±0.80) U/ml and (10.11±1.41) ng/L respectively. In 1 d bowel preparation group the corresponding values were (10.19±1.35) mg/L, (5.80±0.81) U/ml and (9.82±1.35) ng/L respectively. There were no significant differences between 3 d and 1 d bowel preparation group (Pgt;0.05), compared with hernia group, 1 d and 3 d bowel preparation group were also no statistically significant differences (Pgt;0.05). Conclusions There are no significant preoperative gut mucosal barrier function damages in patients with 1 d and 3 d bowel preparation for colorectal carcinoma surgery, 1 d bowel preparation for colorectal carcinoma surgery can be performed in colorectal carcinoma patients, and 3 d bowel preparation can be used for certain special colorectal carcinoma patients.