Background: As a common disease in pediatrics, constipation poses a high burden to the community. In this study, we aimed to investigate the efficacy of dry cupping therapy (an Eastern traditional manipulative therapy) in children with functional constipation. Materials and Methods: One hundred and twenty children (4-18 years old) diagnosed as functional constipation according to ROME III criteria were assigned to receive a traditional dry cupping protocol on the abdominal wall for 8 minutes every other day or standard laxative therapy (Polyethylene glycol (PEG) 40% solution without electrolyte), 0.4 g/kg once daily) for 4 weeks, in an open label randomized controlled clinical trial using a parallel design with a 1:1 allocation ratio. Patients were evaluated prior to and following 2, 4, 8 and 12 weeks of the intervention commencement in terms of the ROME III criteria for functional constipation. Results: There were no significant differences between the two arms regarding demographic and clinical basic characteristics. After two weeks of the intervention, there was a significant better result in most of the items of ROME III criteria of patients in PEG group. In contrast, after four weeks of the intervention, the result was significantly better in the cupping group. There was no significant difference in the number of patients with constipation after 4 and 8 weeks of the follow-up period. Conclusion: This study showed that dry cupping of the abdominal wall, as a traditional manipulative therapy, can be as effective as standard laxative therapy in children with functional constipation.