AIM: To compare between 2 and 4 d colon cleansing protocols. METHODS: Children who were scheduled for colonoscopy procedure (2010-2012) for various medical reasons, were recruited from the pediatric gastroenterology clinic at Marshall University School of Medicine, Huntington, WV. Exclusion criteria were patients who were allergic to the medication used in the protocols [polyethylene glycol (PEG) 3350, Bisacodyl], or chil- dren with metabolic or renal diseases. Two PEG 3350 protocols for 4 d (A) and 2 d (B) were prescribed as previously described. A questionnaire describing the volume of PEG consumed, clinical data, and side effects were recorded. Colon preparation was graded by two observers according to previously described method. Main outcome measurements: Rate of adequate colon preparation. RESULTS: A total of 78 patients were considered for final calculation (group A: 40, group B: 38). Age and stool consistency at the last day was comparable in both groups, but the number of stools/day was significantly higher in group B (P = 0.001). Adequate colonpreparation was reached in 57.5% (A) and 73.6% (B), respectively (P = 0.206). Side effects were minimal and comparable in both groups. There was no difference in children’s age, stool characteristics, or side effects between the children with adequate or inadequate colon preparation. Correlation and agreement between observers was excellent (Pearson correlation = 0.972, kappa = 1.0). CONCLUSION: No difference between protocols was observed, but the 2 d protocol was superior for its shorter time. Direct comparison between different colon cleansing protocols is crucial in order to establish the “gold standard” protocol for children. METHODS: Children who were scheduled for colonoscopy procedure (2010-2012) for various medical reasons, were recruited from the pediatric gastroenterology clinic at Marshall University School of Medicine, Huntington, WV. Exclusion criteria were patients who were allergic to the medication used in the protocols [polyethylene glycol (PEG) 3350, Bisacodyl], or chil- dren with metabolic or renal diseases. Two PEG 3350 protocols for 4 d (A) and 2 d ) were prescribed as previously described. A questionnaire describing the volume of PEG consumed, clinical data, and side effects were recorded. Colon preparation was graded by two observers according to previously described method. A total of 78 patients were considered for final calculation (group A: 40, group B: 38). Age and stool consistency at the last day was comparable in both groups, but the number of stoo Adequate colon preparation was reached in 57.5% (A) and 73.6% (B), respectively (P = 0.206). Side effects were minimal and comparable in both groups. was no difference in children’s age, stool characteristics, or side effects between the children with adequate or inadequate colon preparation. Correlation and agreement between observers was excellent (Pearson correlation = 0.972, kappa = 1.0). CONCLUSION: No difference between protocols was observed, but the 2 d protocol was superior for its shorter time. Direct comparison between different colon cleansing protocols is crucial in order to establish the “gold standard” protocol for children.