There are many different causes of pleural effusion, some of which can be treated with moxibustion, but more pleural effusion may not be as effective with moxibustion, and it is important to be clear about the cause. Some pleural effusions are related to the heart, and if the heart disease is under control, applying the warming effect of moxibustion to move the meridians and collaterals may be of considerable help. If the pleural effusion is caused by infection-related pleural effusion, such as tuberculosis, tumor-related pleural effusion, such as lung cancer, and systemic diseases, such as systemic lupus erythematosus, if the primary disease is not effectively controlled, moxibustion treatment alone is mostly ineffective.