Abstract:Objective To investigate the efficacy and safety of Linaclotide combined with Simethicone oil and compound polyethylene glycol electrolyte (PEG) for cleansing effect of bowel in patients with constipation.Methods A prospective randomized controlled trial was designed and implemented by single blind method. 383 patients with constipation who underwent colonoscopy from April 2023 to August 2024 were enrolled and randomly divided into routine group (128 cases), experimental group A (128 cases) and experimental group B (127 cases). Routine group treated with 3 L PEG, experimental group A treated with 290 μg Linaclotide + 2 L PEG and experimental group B treated with 290 μg Linaclotide + 30 mL Simethicone + 2 L PEG. Bowel preparation effect [Boston bowel preparation scale (BBPS) scores and foaming removal effect], lesion detection rate, first defecation interval, frequency of defecation, the success rate of cecal intubation, the insertion time of colonoscopy, the withdrawal time of colonoscopy, incidence of adverse reactions and willingness to repeat examination of the three groups were compared.Results No statistically significant differences were observed in the BBPS scores among the three groups (P > 0.05); The foaming removal effect score in experimental group B was significantly lower than that in routine group and experimental group A, the difference was statistically significant (P < 0.05); The total lesion detection rate and polyps detection rate of experimental group B were significantly higher than those of routine group and experimental group A, the differences were statistically significant (P < 0.05). The first defecation interval of the routine group was significantly longer than that of experimental group A and experimental group B, the difference was statistically significant (P < 0.05); The frequency of defecation was compared among the three groups, and the difference was no statistically significant (P > 0.05). The success rate of cecal intubation in the three groups was 100.0%, and the insertion time of colonoscopy was similar, the differences were not statistically significant (P > 0.05); The withdrawal time of colonoscopy in experimental group B was significantly shorter than that in routine group and experimental group A, the difference was statistically significant (P < 0.05). The incidence of abdominal distension and total adverse reactions in the routine group were higher than those in experimental group A and experimental group B, the differences were statistically significant (P < 0.05); The willingness to repeat examination rate of the routine group was significantly lower than that of experimental group A and experimental group B, the differences were statistically significant (P < 0.05).Conclusion 290 μg Linaclotide combined with 30 mL Simethicone and 2 L PEG solution regimen has advantages in intestinal preparation for patients with constipation, and can achieve better intestinal cleaning effect than 3 L PEG solution and 290 μg linalopeptide+2 L PEG solution regimen, with higher safety and willingness to repeat examination. It can be recommended for bowel preparation for patients with constipation.