Tuberculosis that is not contagious means that the patient does not excrete Mycobacterium tuberculosis from his or her sputum, and therefore is not contagious. Tuberculosis is an infectious disease of the respiratory system caused by infection with Mycobacterium tuberculosis, and is mainly transmitted by droplets through the respiratory tract. Tuberculosis that is not infectious includes sputum-negative tuberculosis, which is not infectious because no Mycobacterium tuberculosis bacteria are found in the sputum smear. Tuberculous pleurisy is also a type of non-open pulmonary tuberculosis, and the patient’s sputum is also free of Mycobacterium tuberculosis and is not infectious. However, the absence of infectious tuberculosis does not mean that treatment is not needed, and standardized anti-tuberculosis treatment is still required.