Tuberculosis is an infectious disease of the lungs caused by Mycobacterium tuberculosis infection and is usually not contagious after about 2 months of treatment. Tuberculosis is infectious and can be transmitted through the respiratory tract. Sputum from patients with positive sputum smears and untreated tuberculosis is the main source of infection. First-line drugs for TB include isoniazid, rifampin, streptomycin, and pyrazinamide; second-line antibacterial drugs include ethambutol and sodium 4-aminosalicylate. Usually patients with pulmonary tuberculosis are treated according to the principles of early, combined, regular, moderate and full treatment for about 2 months, and they should go to the hospital to review sputum bacteria and chest X-ray. If the sputum bacillus test turns negative and the X-ray examination of the lesion is absorbed and hard nodules are the indicator, it usually suggests that there is no infectiousness. Patients with tuberculosis are advised to follow the doctor’s instructions when treating the disease and not to stop or change the dosage without permission, so as to avoid incomplete treatment and relapse.