Pellagra is a disorder characterized by dermatitis, diarrhea, dementia and eventually death, resulting from a deficiency of niacin or its precursor tryptophan. Ethionamide (a second-line antituberculosis agent)-induced pellagra is rarely encountered in clinical practice. Prompt diagnosis and treatment with nicotinamide can prevent life-threatening complications. To date, only three cases have been reported. We report a 13-year-old girl presenting with ethionamide-induced pellagra that resolved after the administration of niacin.