The authors evaluated the efficiency of a routine drug therapy regimen by the WHO category 1 in treating 149 new cases of destructive pulmonary tuberculosis and bacterial isolation. They used not only the WHO sputum smear negativization criterion, but the data of cultural studies and on lung cavernous closure. The specific features of the approach applied were compulsory cultural studies determining Mycobacterium sensitivities before treatment and compulsory correction of chemotherapy after there was evidence for the sensitivity. Retrospective analysis of 6-month chemotherapy has ascertained that the efficiency of the routine drug therapy regimen largely depends on the baseline extent of infiltrative and destructive changes in the lung and on the baseline resistance of Mycobacteria tuberculosis. They showed a high baseline resistance to streptomycin (20.6%) and streptomycin and isoniazid (33.1%) and a low baseline resistance to ethambutol (5.1%). In these cases, the more optimum regimen was a combination of rifampicin, pyrazanamide, and ethambutol. When Mycobacteria showed multidrug resistance, the routine regimen was ineffective and caused amplification to a larger number of drugs. A modified treatment course using the routine regimen in the intensive phase was developed. If Mycobacterial resistance was present, compulsory correction was made by using reserve agents, pathogenetic treatments, artificial pneumothorax or surgical interventions, which made it possible to abacillate 94.1% of patients by their smears and culture by months 4-5 and to close caverns in 91.3% of cases by months 8-10.