Polyethylene glycol (PEG), particularly PEG 3350, is widely recognized as a first-line therapy for treating constipation in children. Its use is strongly supported by scientific evidence. PEG is an osmotic laxative: it works by retaining water in the stool, resulting in softer stools and promoting bowel movements. Several high-quality randomized controlled trials (RCTs) and systematic reviews have demonstrated the efficacy and safety of PEG in pediatric populations with functional constipation.

The 2014 ESPGHAN/NASPGHAN guidelines recommend PEG as the first-choice medication for both disimpaction and maintenance therapy in children with constipation, based on robust clinical evidence. Studies comparing PEG with other laxatives such as lactulose indicate that PEG is at least as effective, if not superior, in increasing stool frequency and improving stool consistency, with a favorable side effect profile. The Cochrane Reviews also highlight PEG's efficacy and safety, with adverse effects being generally mild and infrequent (e.g., abdominal pain, diarrhea).

PEG’s use in children is not based on tradition but is instead grounded in well-conducted clinical research. It is recommended by major pediatric and gastroenterological organizations worldwide, making it a scientifically validated and preferred option for treating constipation in children.