Semen comes out by itself while sleeping, which belongs to the manifestation of dream emission. If this phenomenon occurs occasionally, it is considered to be a normal physiological phenomenon. If this phenomenon occurs frequently, or other uncomfortable symptoms, we should consider the possibility of pathological factors. 1. Normal phenomenon: For adolescent and adult males, the reproductive organs will continue to produce sperm. If they are not discharged in a timely manner for a long period of time, the sperm will remain in the body. When stimulated during sleep, the phenomenon of ejaculation may occur. 2. Abnormal phenomenon: if frequent wet dream, or at the same time the perineum swelling and pain, dizziness, fatigue, difficulty concentrating and other symptoms, we should consider the possibility of prostatitis, circumcision and other disease factors. Prompt medical attention is needed. For men with frequent symptoms, they should seek medical advice as soon as possible to confirm the diagnosis, and after clarifying the condition, treatment should be carried out under the guidance of the doctor.