The presence of cavities in tuberculosis may be caused by necrosis and liquefaction of lung structures by Mycobacterium tuberculosis. If Mycobacterium tuberculosis grows and multiplies in large numbers in the lungs, it destroys normal lung tissues and causes them to become necrotic and liquefied. Substantial damage to localized lung tissues and organs may be manifested by the appearance of cavities, which are relatively serious. The presence of cavities in the lungs of TB patients is usually a symptom of a longer course of the disease, when sputum tests are usually positive and highly infectious. Cavity lesions may cause Mycobacterium tuberculosis to spread further in the lungs, leading to further progression of the disease. It may also damage the patient’s lung tissue, resulting in destruction of lung cells and other conditions, seriously affecting lung function. When a patient develops a cavity in his or her TB, it is recommended that he or she seek timely medical attention and be given early, adequate and regular anti-tuberculosis treatment. Avoid the cavity to continue to expand and destroy the whole lung organ.