Two new short-term therapy programs for tuberculosis (TB), based on twice-weekly chemotherapy with isoniazid and rifampin, have been developed recently by the Public Health Service (PHS) and by the Arkansas State Department of Health. Although similar in design and intent, the two programs have had substantially different results. While current TB therapy programs in this country have proved acceptable, the promise of quicker results, higher patient compliance with the treatment protocol, curtailed side effects, and much greater cost-effectiveness has inspired the experimental short-course regimens. The Arkansas program, which uses nurse practitioners in the field to ensure that patients comply with the prescribed therapy, has been highly successful. The PHS program, relying for the most part on voluntary compliance, has been less so. Both therapy regimens use isoniazid and rifampin at similar doses. The Arkansas program calls for initial treatment with isoniazid, 300 mg, and rifampin, 600 mg, in single daily