Infection is considered when there is pus flowing from the genitals. The most common diseases of infection: First, gonorrhea, which is the most common cause of purulent discharge from the genital tract of the urinary tract, is a sexually transmitted disease. It is caused by the process of sexual transmission resulting in gonococcal infection of the urethra, which is typically characterized by frequent urination, urinary urgency, painful urination accompanied by yellow purulent discharge from the urethra. The duration of the disease is relatively long, and if not treated in time, it may cause urethral stricture at a later stage. It is recommended to perform pus culture examination, and if gonococcus is cultured, anti-infection treatment is needed. Second, non-gonorrhea, non-gonococcal urethritis, that is, caused by mycoplasma, chlamydia infection. It is also characterized by frequent urination, urinary urgency, pain in the urethra with burning sensation in the urethra, and yellow or white thin pus-like discharge from the urethral orifice. The treatment and confirmation of the diagnosis require the retention of pus for culture. Third, acute purulent inflammation, usually caused by bacterial secondary infection, with frequent urination, urinary urgency, the urethral orifice flowing pus, confirming the diagnosis still need to take pus for further bacterial culture to confirm the diagnosis, treatment is mainly anti-infective treatment.