The time it takes for a small amount of pleural effusion to resolve on its own varies from person to person and is related to the patient’s physical condition and the type of disease causing the pleural effusion. If the small amount of pleural effusion is caused by simple trauma, such as lung contusion and chest wall injury causing increased exudation, and the patient is young, with respiratory function exercise, the pleural effusion can be completely absorbed in about 1-2 weeks. If the patient is older and has a large amount of pulmonary atelectasis, the effusion will be absorbed more slowly. If a small amount of pleural effusion is caused by the patient’s prolonged bed rest causing pneumonic pneumonia, the pleural effusion may increase if the patient is still unable to get out of bed and move around. If the patient can get out of bed, the effusion can be absorbed quickly after activity. For tuberculous pleural effusion, its absorption is slower and usually takes 2-3 weeks or even more than 1 month to be completely absorbed. Patients need to pay attention to improving immunity and strengthening nutrition, which can help promote the absorption of effusion. They should be given a diet with high energy, high protein and vitamin-containing food, and pay attention to keeping sufficient rest and regular rest and rest.