Three cases of children who developed hepatic toxicity of different degree while on antituberculous treatment with isoniazid and rifampicin are reported. The clinical picture is presented and the pathogenesis of the hepatic damage is discussed. The pathological findings in the liver are those of a drug induced hepatitis. The combined treatment of tuberculosis in children with isoniazid and rifampicin is potentially dangerous and should be reserved for cases in which resistance to other drugs has been demonstrated.