Tuberculosis (TB) is only infectious in some patients who have a large amount of tubercle bacilli in their sputum. In fact, many patients with active pulmonary tuberculosis are not infectious. For more patients with active pulmonary tuberculosis, tubercle bacilli cannot be found in their sputum, so the actual situation must be considered. In fact, to determine if pulmonary tuberculosis is infectious, it is simple: look for acid-fast bacilli in the sputum. If the sputum acid-fast staining is positive, it indicates infectiousness. Infectious pulmonary tuberculosis requires systematic and standardized anti-tuberculosis treatment.