In this randomized controlled study, consecutive outpatients scheduled for elective colonoscopy were randomized into two groups. Group A patients (n = 300) used only 3L PEG before colonoscopy. Patients in group B (n = 300) were additionally advised to Dyclonine Hydrochloride Mucilage plus 3L PEG, The overall quality of colonoscopy cleaning was evaluated using the Boston Bowel Preparation Scale by a single endoscopist who was blinded to the intervention. Visibility was blindly assessed for the amount of air bubbles and adenoma detection rate (ADR). Difficulty of procedure, and adverse events were also evaluated.

Inclusion Criteria:

1. Patients are between 18-75 years old
2. undergoing colonoscopy for diagnostic investigation, colorectal cancer screening or follow-up

Exclusion Criteria:

1. suspected gastrointestinal obstruction or perforation
2. severe acute inflammatory bowel disease
3. toxic megacolon
4. ileus or gastric retention, ileostomy,
5. hypersensitivity to any of the ingredients
6. pregnancy and lactation and/or at a risk of becoming pregnant