Clinical updates in bowel preparation for colonoscopy

Colonoscopy is essential for colorectal cancer (CRC) screening, but its effectiveness depends on adequate bowel preparation (BP), which remains suboptimal in up to 44 % of cases. Poor BP reduces lesion detection, particularly in the proximal colon, and increases procedure time, repeat exams, and healthcare costs. This narrative review summarizes evidence-based strategies to improve BP, highlighting high- and low-volume polyethylene glycol (PEG) regimens, including newer very-low-volume options with better patient tolerance. Adjunctive agents like simethicone and 5-HT4 agonists benefit select groups, especially those with constipation. Split-dose and same-day regimens, particularly with a <5-h interval before the procedure, enhance cleansing and adenoma detection. A 1-day low-fiber diet is now preferred for better compliance. Risk factors for poor BP include age, comorbidities, and socioeconomic barriers. Emerging tools, such as predictive models and AI-enabled apps, support personalized care. A patient-centered, risk-adapted approach is vital to optimize colonoscopy quality and reduce CRC incidence.