Abstract:Abstract: OBJECTIVE To explore the differences of adverse reactions and final defecation between two different medication methods of compound polyethylene glycol electrolyte powder in patients with bowel preparation before colonoscopy. METHODS A to⁃ tal of 309 patients who underwent colonoscopy in PLA Rocket Force Characteristic Medical Center from February 2022 to February 2023 were enrolled. Patients were divided into single-dose group (n=134) and split-dose group (n=175). The single-dose group took 3 L Compound polyethylene glycol electrolyte solution on the morning of the examination, and the split-dose group took 1.5 L Compound polyethylene glycol electrolyte solutionon the evening before the examinationand the other 1.5 L on the morning of the ex⁃ amination. The adverse reactions, tolerance and final defecation of the two groups were compared. RESULTS There was no statistical significance in the completion degree of administration and the proportion of patients with severe abdominal distension who had ≥ 10 defecation times between the two groups (P>0.05). The proportion of patients with severe abdominal pain, the proportion of pa⁃ tients with the overall feeling score of 0~3, the proportion of patients with the last stool trait score of C/D in the grading group were higher than those in the single group, and the proportion of patients with vomiting symptoms was lower than that in the single group, with statistical significance (χ 2 =3.405, 2.955, 3.738, 8.407, P<0.05). No adverse reactions or complications occurred in both groups. CONCLUSION Compared with the two different administration methods of compound polyethylene glycol electrolyte powder, the inci⁃ dence of body discomfort was lower and the patients felt more comfortable in the divided group, and the divided group was better than the single group in terms of the effect of last defecation.