Functional constipation is a common condition in children and often requires prolonged maintenance treatment with macrogol. This randomized, double-blind, placebo-controlled trial will evaluate whether co-supplementation with Bifidobacterium longum W11 and Colopectin can support maintenance therapy in children with functional constipation who are receiving macrogol and are candidates for weaning. Participants aged 2 to 6 years will be randomized to receive either the active supplementation or placebo once daily for 4 weeks, followed by 4 weeks of follow-up after treatment discontinuation. The study will assess persistence of constipation after macrogol discontinuation, as well as stool consistency, distress during evacuation, soiling episodes, and treatment compliance.