Heat is the name of a disease in traditional Chinese medicine. It refers to internal heat. "Suwen·Mai Yao Jingwei Lun" says: "Those with thick and large pulses are caused by insufficient yin and excessive yang, which is heat." Li Shizhen of the Ming Dynasty quoted Li Gao in "Compendium of Materia Medica·Cao Qi·Morning Cow Seed" (Collected Explanations): "What's more, if the diet is not regular and the labor is injured, the stomach qi is not working, and the fire takes over, and the stomach and intestines are affected by the fire evil, which is called heat." Heat is also called internal heat, and in traditional Chinese medicine it is also called "internal fire and heat". As the name suggests, internal fire (heat) is a type of disease caused by excessive metabolism and excessive heat production in the human body, which is the opposite of internal cold. Excessive heat production can be either absolute or relative. Absolute excess refers to the disease caused by excessive metabolism of the human body, which leads to heat production exceeding the normal heat dissipation capacity; while relative excess refers to the disease caused by the decrease in the heat dissipation capacity of the human body, which leads to relative excess heat production.