Heat injury refers to the exuberance of yang heat, resulting in the depletion of fluid. Clinical manifestations include fever, face redness, restlessness, thirst, short yellow urine, dry stools, and red tongue with yellow fur. Injury to fluids by heat is caused by the prevalence of yang heat, which depletes yin and fluids, resulting in a deficiency of yin fluids and a decrease in the functions of nourishment and moistening. The common clinical manifestations of heat injury to fluids are: fever, dry mouth and throat, thirst for cold drinks, hunger, irritability, yellow and thick phlegm, sunken eyes, contractures of the hands and feet, or even the back and neck are straightened and the horns are torn, the skin is dry and shriveled, the urine is short and yellow, the stool is dry and knotty, or even abdominal distension and constipation, the tongue is red with little fluids, the moss is yellow and dry, and the pulse is fine and numb (the pulse is becoming narrower and finer, and its rate is accelerated), etc. The above symptoms should be checked promptly by a doctor. The above symptoms should be treated by a doctor in time, and should not be treated blindly by oneself.