Objective:To investigate the effects of glycopyrrolate on intestinal spasm and hemodynamics in painless colonoscopy.Methods:A total of 100 patients who were scheduled to undergo painless colonoscopy were selected as the study subjects and randomly divided into two groups by a computerized number method. Ten patients in both groups dropped out because of disruption of the study protocol, and 45 patients from each group were included in the final analysis. Before anesthesia induction, patients in group glycopyrrolate (group G) were injected with 0.2 mg glycopyrrolate, while those in congtrol group (group C) were injected with an equal amount of saline. The heart rate, systolic blood pressure, and diastolic blood pressure were recorded at T 0 (baseline period), T 1 (after anesthesia induction), T 2 (colonoscopy over sigmoid colon), T 3 (colonoscopy over the liver region), T 4 (after the end of examination), and T 5 (at the awakening phase), and the degree of intestinal spasm was assessed intraoperatively using the Likert′s four-point scale. The numerical rating scale (NRS) was used to assess preoperative and postoperative pain. The incidence of adverse events was recorded. Results:The general data at baseline were not statistically different between the two groups ( P>0.05). During the procedure, patients in group G had lower intraoperative intestinal spasm scores than those in group C ( P=0.028). Intraoperative hypotension and bradycardia occurrence were lower in group G than in group C ( P<0.05), and intraoperative norepinephrine use was also lower than in the group C ( P=0.034). Postoperative visual analog scale pain scores were lower in group G ( P=0.047), but patients who used glycopyrrolate had a higher proportion of dry mouth ( P=0.035). Conclusion:During painless colonoscopy, preoperative administration of glycopyrrolate significantly improved intraoperative hemodynamic fluctuations, reduced the incidence of hypotension and bradycardia, and relieved postoperative pain. However, glycopyrrolate use resulted in the risk of dry mouth.