The main cause of nocturnal emission is the weakening of cerebral cortex inhibition process and the enhancement of sexual center excitability. When there is sexual stimulation, nocturnal emission often occurs. Underwear is too tight, skin scales irritate, balanitis prepuce, inflammation of urethra, prostate and seminal vesicle, etc. , may cause nocturnal emission. For the treatment of etiology, we should first understand sex, avoid excessive excitement of sexual organs, strengthen physical exercise, enhance physical fitness, and focus on study and work. I wish you the best of health!