It is also called night sweat, which is a more common symptom in clinical diseases. Its pathogenesis is mostly caused by yin deficiency and internal heat, such as overexertion, loss of blood and essence or heat that consumes yin, resulting in deficiency of yin and essence, internal growth of deficiency fire, disturbance of yin and essence, which cannot hide itself and leak out, resulting in night sweat, but also spontaneous sweating, five heartburn or afternoon hot flashes, red cheekbones, dry throat and thirst, red tongue with little coating, thin pulse, etc. The treatment is to nourish yin and lower fire.