Yomesan—N-(2′-chlor-4′-nitrophenyl)-5 chlorsalicylamid—was ineffective in 10 children with Hymenolepis nana infections who were treated with a single dose of 100 mg per kg of body weight. On the other hand, at least 90% of 62 children who received 40 to 80 mg per kg per day for 5 days were cured as evidenced by negative stool examinations performed weekly or biweekly for 10 to 12 weeks after treatment. Nine untreated children used as controls and similarly examined remained positive throughout the observation period. No objective signs of intolerance or toxicity were noted. In view of the world-wide reports of the efficacy and safety of Yomesan (niclosamide) in the treatment of Taenia infections and its extensive use in many parts of the world, we suggest that this drug be made available in the United States.