Treatment of tuberculosis: A 6-month regimen consisting of isoniazid, rifampin, and pyrazinamide given for 2 months followed by isoniazid and rifampin for 4 months is effective treatment in patients with fully susceptible organisms who comply with the treatment regimen. It may be advisable to include ethambutol in the initial phase when isoniazid resistance is suspected. A 9-month regimen consisting of isoniazid and rifampin is also highly successful. The need for an additional drug in the initial phase is not certain unless isoniazid resistance is suspected, in which case ethambutol should be included until susceptibility tests have been reported. In the presence of documented resistance to isoniazid, rifampin and ethambutol, perhaps supplemented initially by pyrazinamide, should be given for minimum of 12 months. Children should be treated in essentially the same ways as adults using appropriately adjusted doses of the drugs. However, consideration must be given to the important differences in the approach to management in children. Extrapulmonary tuberculosis should be managed according to the principles and with the drug regimens outlined to pulmonary tuberculosis. The major determinant of the outcome of treatment is patient compliance. Careful attention should be paid to measures designed to foster compliance and to ensure that patients take the drugs as prescribed. Treatment of tuberculous infection: Preventive therapy with isoniazid given for 6 to 12 months is effective in decreasing the risk of future tuberculosis. (ABSTRACT TRUNCATED AT 250 WORDS)