Pleural effusion in the elderly is usually not life threatening if it is caused by benign diseases and actively treated. If it is caused by heart failure or pleural metastasis from a malignant tumor, treatment is not effective and may be life threatening. Pleural effusion in the elderly may be caused by benign diseases, heart failure. Inflammatory diseases, hypoproteinemia and other benign diseases caused by timely and correct treatment can generally be cured and will not be life-threatening. Heart failure caused by coronary artery disease, heart valve disease, cardiomyopathy, etc. may be life threatening if the primary disease is not relieved in time. Pleural effusion in the elderly may also be caused by malignant tumors, which will disappear in some patients after active treatment, with a long overall life expectancy. Some patients with malignant tumors do not respond well to treatment, and pleural effusions continue to develop and may be life threatening. If an elderly person develops pleural effusion, he or she should go to the hospital in time for examination, make a clear diagnosis under the guidance of the doctor, and undergo targeted treatment as early as possible to relieve the pleural effusion.