Massive hemoptysis is one of emergency and critical diseases of the respiratory system. The definition of massive hemoptysis has always been different in the literature, which often depends on the quantitative estimation of the amount of hemoptysis, such as the amount of hemoptysis being in the range of 300-600 mL within 24 h, or hemoptysis more than 3 times within 1 week. Each amount of hemoptysis that is greater than 100 mL can be considered as massive hemoptysis, but the amount of hemoptysis is difficult to accurately estimate. Therefore, massive hemoptysis can be defined as any life-threatening hemoptysis and any hemoptysis that may cause airway obstruction and asphyxia. Massive hemoptysis accounts for approximately 5% of all hemoptysis cases and usually indicates the presence of a potentially severe respiratory or systemic disease. The mortality rate of massive hemoptysis is about 6.5-38%. The cause of death is generally shock caused by airway obstruction or excessive bleeding, and asphyxia is the main cause of death. At present, due to insufficient understanding of massive hemoptysis, there are limited technical means in the etiological diagnosis and untimely or improper treatment, resulting in high mortality of massive hemoptysis. Therefore, the diagnosis and treatment of massive hemoptysis needs to be standardized. © 2019 S. Karger AG, Basel. All rights reserved.