The aim of this study was to assess the efficacy of a solution composed by verbascoside, polyvinylpyrrolidone, and sodium hyaluronate (Mucosyte) in the treatment of chemotherapy-induced oral mucositi (OM). Patients between 5 and 18 years receiving chemotherapy for acute lymphoblastic leukemia and with OM grade 1 or 2 were randomized in group A (treated with Mucosyte, 3 mouthwashes/d per 8 d) and group B (treated with placebo, ie, an inert water-based solution, 3 mouthwashes/d per 8 d). The OM scoring was performed at day 1 (diagnosis of OM-T0), after 3 days of treatment (T1), and at day 8 (T2). Pain was evaluated through the visual analog scale with the same timing of OM measurement. A total of 56 patients were included (28 patients per group). Group A experienced a statistically significant decline of OM at T2 (P=0.0038); a statistically significant difference in pain reduction between 2 groups both at T1 and at T2 (P<0.005) was observed. The use of Mucosyte mouthwashes in children with chemotherapy-induced OM may be recommended as supportive therapy.