Inclusion Criteria:  Consecutive patients (aged 18-80 years) scheduled for colonoscopy examination.  Exclusion Criteria:  Patients with a history of inflammatory bowel disease, advanced colorectal cancer, polyposis syndromes or known colorectal polyps without complete removal previously. Patients with a history of colorectal surgery. Patients with a contraindication for biopsy. Patients with prior failed colonoscopy. Patients with known stenosis or obstruction. Patients in pregnancy or lactation phase. Patients refused to participate in the trial.