In this randomized controlled trial, consecutive outpatients with constipation for colonoscopy are screened and then randomized into two groups. All enrolled patients will receive 3 liter polyethylene glycol (PEG) for bowel preparation. Patients in the chewing gum and WeChat group (n = 75) are further advised to chew one piece of sugarless gum for 20 minutes after drinking each 1 liter PEG; additionally, they will receive enhanced instructions via WeChat before two days and one day of colonoscopy to further inform how to chew gum and highlight the importance of adequate bowel preparation. Patients in the control group (n = 75) are guided by regular instructions.
Patients with constipation are more likely to have poor bowel preparation quality due to slow gut motility and poor emptying ability. Gum chewing, as a proxy of sham feeding, is a very simple way used to accelerate gut motility. And a previous study found that enhanced instructions by WeChat could improve bowel preparation quality. Thus, investigators conducted a single-center randomized controlled trial to explore the effect of chewing gum combined with manual enhanced instructions by WeChat on the bowel preparation quality for colonoscopy in patients with constipation.