ABSTRACTObjectives:We have recently reported the safety and efficacy of polyethylene glycol 3350 without electrolytes (PEG) for the daily treatment of constipation in older children. Because there are very few data available on the use of PEG in infants and toddlers, we evaluated the efficacy and safety of PEG for the treatment of constipation in children <2 years of age.Methods:This is a retrospective chart review of 75 constipated children <2 years of age at start of PEG therapy. PEG was started at an average dose of 1 g/kg body weight/d and parents were asked to adjust the dose to yield 1 to 2 soft painless stools/d. Data from the history and physical examination were collected initially and at short‐term (≤4 months) and long‐term (≥6 months) follow‐up.Results:75 otherwise healthy children received PEG for functional constipation. The mean age was 17 months (range, 1 to 24 months) and the mean duration of constipation was 10 months (range, 0.5 to 23 months). The mean duration of short‐term follow‐up was 2 months and mean duration of long‐term follow‐up was 11 months. The mean effective short‐term PEG dose was 1.1 g/kg body weight/d and the mean long‐term dose was 0.8 g/kg body weight/d. Constipation was relieved in 85% with short‐term and in 91% with long‐term PEG therapy. Adverse effects were mild and included diarrhea, which disappeared with lowering the dose. No subjects stopped PEG because of adverse effects.Conclusion:PEG is effective, well tolerated and appeared safe for the treatment of functional constipation in children <2 years of age.