A fluid in the lungs is a pleural effusion. It is the most common type of pulmonary tuberculosis caused by Mycobacterium tuberculosis infection in the lungs. Firstly, anti-tuberculosis drugs should be administered in a standardized, appropriate amount, throughout the whole process and in combination; secondly, if pleural effusion affects the respiratory function of the lungs, thoracentesis can be performed to drain the fluid to restore the normal respiratory movement of the lungs, improve the ventilation and airflow of the lungs, and prevent respiratory failure from occurring. Lastly, if necessary, local treatment with anti-tuberculosis drugs and adrenocorticotropic hormone can be injected into the chest cavity to promote the dissipation of fluid in the lungs.