Baihu Jia Renshen Decoction recorded in Treatise on Febrile Diseases by Zhang Zhongjing in the Han Dynasty could be used to clear heat,invigorate Qi,and promote fluid production. The indications of Baihu Jia Renshen Decoction include infectious diseases,such as lung infection,influenza,encephalitis,enteric typhoid and hospital infection; thermoplegia; acute cerebrovascular disease,diabetes mellitus,severe hyperosmolarity,hypernatremia,intractable hypotension,shock and other internal diseases; sweating,irritation,thirst,want to drink several liters of water,dry mouth,dry tongue,and big pulse. This prescription has been widely used to treat acute and severe cases in the cardiovascular intensive care ward. The prescription can be used to treat exogenous and internal injury diseases,which are characterized by excessive heat,fluid injury,thirst for water,dry mouth,dry tongue and other symptoms; refractory hypotension and hypovolemic shock that need large dose of supplemental fluid to maintain blood pressure and may also belong to the extension of the Baihu Jia Renshen Decoction formula syndrome; severe hyperosmolarity and hypernatremia needing nasal feeding with large quantities of sterile water or cool boiled water that may also belong to the extension of the Baihu Jia Renshen Decoction formula syndrome; the four major symptoms,namely severe heat,excessive perspiration,great thirst,and large-bounding pulse,are actually the indications of Baihu Jia Renshen Decoction,rather than Baihu Decoction. Severe irritability should also be added into the indications of Baihu Jia Renshen Decoction; severe heat refers to pathogenesis,rather than a symptom.