Background: Adequate bowel cleansing is essential for effective and safe colonoscopy. However, standard 4 liters or low volume 2 liters bowel preparation regimen uses a lot of water that cause pain in patients.

Objective: To compare the degree of colon cleansing using 2-liter split-dosage and 2-liter non-split-dosage and evaluate the outcome from bowel preparation.

Materials and Methods: This study was a single-blind, randomized study, which conducted in tertiary-care institutions. All enrolled patients who underwent colonoscopy were randomized to receive 2-liter split-dose polyethylene glycol [PEG] or 2-liter non-split-dose PEG. The bowel preparation scale and questionnaires were evaluated after the procedure.

Results: One hundred and eighty patients were evaluated in this study, 91 patients received 2-liter split-dose and 89 patients received 2-liter non-split-dose PEG. Boston bowel preparation scale [BBPS] scores were not significantly different in both groups (8.7+0.6 in 2-liter spilt group vs. 8.6+0.6 in 2-liter non-split group, p = 0.25). Cecal intubation rate, willingness to repeat colonoscopy and overall satisfaction were also not different in both groups. However, more patients chose 2-liter spilt-dose regimen than 2-liter non-split regimen for the next colonoscopy (66.7% vs. 33.3%, p = 0.003).

Conclusion: Two-liter split-dose PEG was as effective as two-liter non-split-dosage for bowel cleansing in colonoscopy. However, split dose has superior palatability compared to non-split dose.

Keywords: Boston bowel preparation scale, Bowel preparation, Colonoscopy, Non-split-dose, Polyethylene glycol, Split-dose