Aim: To evaluate the performance of an SHM scheme (streptomycin, isoniazid, and ethambutol) in an outpatient clinic routine treatment for tuberculosis. Method: Seventy-eight patients with tuberculosis whose prior treatment with the RHZ scheme (six months of rifampicin, isoniazid, and pyrazinamide) had to be discontinued due to adverse effects, or who could not receive the RHZ scheme due to high risk for liver toxicity, were treated in the outpatient clinic with the 12 month SHM scheme from 1986 to 1994, in the city of Porto Alegre, Rio Grande do Sul, Brazil. Results: Three patients (3.8%) required a scheme change due to toxicity. In the remaining 75 patients, 58 (77.3%) were cured, eight (10.7%) withdrew, five (6.7%) presented failure, and four (5.3%) died. Theoretical cure rate, which is the percent of cure of patients who regularly followed the treatment, was 95.3%. Adverse reactions were seen in 32 patients (41%), the most frequent being vestibular damage in 18 patients (23.1%). Results were compared to those obtained in the same outpatient clinic with the 12 month RHM scheme (rifampicin, isoniazid, and ethambutol), and with the six month RHZ scheme. Conclusion: The SHM scheme may be recommended as an alternative for the treatment of tuberculosis whenever the RHZ scheme cannot be indicated.