Objective: To compare the efficacy of topical treatment with potassium hydroxide at different concentrations with that of placebo in terms of complete clearing of molluscum contagiosum lesions and to assess the safety and tolerance of topical treatment with potassium hydroxide. Methods: A double-blind randomized clinical trial was conducted. A total of 53 children, aged 2–6 years, were assigned into 3 groups. Ten percent of potassium hydroxide 10%, 15% of potassium hydroxide, and placebo were applied once daily up to complete clearing of lesions (maximum duration 60 days). Results: The main efficacy outcome was 58.8% in the 10% potassium hydroxide group (P=0.03 vs placebo) and 64.3% in the 15% potassium hydroxide group (P=0.02 vs placebo). Two potassium hydroxide groups were not significantly different in efficacy from each other. The 10% potassium hydroxide group and the placebo group were better tolerated than the 15% potassium hydroxide group. Subjects receiving 10% potassium hydroxide and placebo had higher proportions of adverse events than those receiving 15% potassium hydroxide. Conclusion: Potassium hydroxide (10% and 15%) demonstrated high rates of efficacy in clearing molluscum contagiosum lesions, and 10% potassium hydroxide is better tolerated.