Gum chewing is known to have a positive effect on intestinal motility. Most studies have examined its effect on ileus, but there has been no discussion of the effects of polyethylene glycol used in preparation for colonoscopy. The purpose of this study was to determine the effect of gum chewing on abdominal pain and nausea caused by polyethylene glycol solution used for intestinal cleansing before colonoscopy. The study was planned as a single-center, randomized, controlled experimental study. The research sample was determined using power analysis (n = 60). Consecutive patients undergoing colonoscopy were randomized into the experimental and control groups. Patients in the gum group chewed mint-flavored sugar-free gum for 20 minutes every 2 hours until the start of colonoscopy after consuming 2 L of polyethylene glycol solution. Patients in the control group drank only polyethylene glycol solution. Examination of precolonoscopy pain and nausea revealed a statistically significant difference in the gum chewing group (p < .05). Patients using sugar-free gum experienced statistically significant fewer problems after colonoscopy. Gum chewing had a positive effect on abdominal pain and nausea. There are no drawbacks to presolution chewing, and it may be recommended for patients.