Nocturnal emission refers to involuntary discharge of seminal fluid without sexual intercourse. It is usually caused by kidney deficiency and weakness of the seminal gate or hyperactive monarch fire and minister fire, downward movement of damp heat, which disturb the seminal vesicle. Seminal emission during dreamful sleep is referred to s nocturnal emission; while that during dreamless sleep r when being awake is termed as spontaneous emission.

The major causes of the disease may be indulgence in sexual activities, weak congenital constitution, mental train, anxiety for seeking sexual pleasure and improper diet. Etiologically, its occurrence is usually closely relevant to the impaired heart, liver and kidneys. Apart from deficiency of the kidneys and inability to arrest semen, hyperactivity of heart fire and liver fire can also impair he renal ability to store essence. Nocturnal emission, in western medicine, may be present in neurasthenia and prostatitis.