Effective antituberculous drugs have radically improved the prognosis of the patient with active tuberculosis. Surgical therapy is rarely needed, and sanitoriums have largely vanished. Triple-drug therapy may be indicated initially for cavitary pulmonary disease, meningitis, miliary disease, and moderate to severe renal disease. Short-course therapy twice or three times weekly with isoniazid and rifampin may be used in cavitary pulmonary disease and probably in these other serious infections as well. Isoniazid alone is adequate for prophylaxis. The major cause of therapeutic failure is noncompliance of the patient in taking the medication regularly. The second major cause of treatment failure is resistance of tubercle bacilli to the antimicrobial agents used. When treatment failure is apparent, careful reassessment by physicians experienced in the treatment of tuberculosis is indicated. A single drug should never be added to a failing regimen.