According to the review of the past literatures, the chemotherapy for silico-tuberculosis in the earlier days was almost unsuccessful. The present paper reports the follow-up studies of all the originally or retreated cases with silicotuberculosis, 140 in number, admitted to our hospital during the past 28 years . The results were summarized as follows: 1. Fourty-three previously untreated cases with positive sputum for tubercle bacilli, were treated with the combination of primary

more »

... us drugs, SM, INH, and PAS. The negative conversion of tubercle bacilli in sputum was seen in 40 cases (93.0%), however, the bacteriological relapse was observed in 11 cases (27.5%) within three years. 2. Sixty-one previously treated cases with positive sputum for tubercle bacilli, were treated with regimens containing primary and/or secondary antituberculous drugs. Only 30 cases (49.2%) converted to negative, while the others showed continuous bacilli discharge. 3. The rate of bacteriological relapse before the introduction of RFP was higher in silico-tuber culosis than in tuberculosis of similar extent without complicating silicosis. These results indicate that bacteriological relapse is the important factor causing clinical aggravation of the disease.