The treatment of lymph node tuberculosis has been studied in 108 patients. Chemotherapy consisted of 18 months' isoniazid with either rifampicin or ethambutol, plus an initial supplement of streptomycin. These 2 regimens were randomly allocated to 19 patients who had previously undergone excision of the lymph nodes, 56 patients who had undergone biopsy and 33 patients who had not had any surgical procedures. The majority of patients were of Indian or Pakistani origin (80%). Histological evidence of tuberculosis was obtained in 64% of the 108 patients and M. tuberculosis was cultured in 30%. No other mycobacteria were grown. Progress during treatment was uneventful in 65% of patients. Fresh nodes appeared during treatment in 12%, existing nodes enlarged in 13% and fluctuation developed in 11% of patients. Discharge and/or sinus formation was infrequent (7%), as was breakdown of a surgical scar (4%). Excision or aspiration after the start of chemotherapy was performed in 19% of patients. In the period up to the end of chemotherapy no difference emerged between the patients who received rifampicin with isoniazid and those who received ethambutol with isoniazid. Satisfactory results were obtained in 98% of the patients by the end of treatment although 13% still had slight node enlargement. The place of surgery is discussed. Follow-up will continue for 18 months after the end of chemotherapy.