The causes of urethritis mainly include pathogenic bacterial infections such as Neisseria gonorrhea, Mycoplasma, Chlamydia and bacteria. According to the different pathogenic bacteria, it is mainly divided into gonococcal urethritis, nongonococcal urethritis and bacterial urethritis. Gonococcal urethritis and nongonococcal urethritis urethritis are mainly infections transmitted through sexual contact. Gonorrheal urethritis is caused by infection with Neisseria gonorrhoeae, commonly known as “gonorrhea”. Gonorrhea is usually acute, with painful urination and purulent discharge. Non-gonococcal urethritis (NGU) is an infection of the urethra caused by pathogens other than Neisseria gonorrhea. It can be carried by normal people without causing disease, and if it does develop, the clinical picture may include urinary tract irritation. 20% to 50% of the population has no clinically significant symptoms. Symptoms may occur when the body is immunocompromised, and accompanying symptoms include discomfort with urination, accompanied by increased urethral discharge, which is plasma or plasma-purulent, thin, and low in volume. In a few cases, urethral secretions can be purulent, and even blood, some people have urethritis will also lead to a decline in sperm quality, women will also have increased leukorrhea, yellow or bloody, non-menstrual or post-coital hemorrhage, cervical congestion, edema, and in the gestation period of the fetus, pre-marital and pre-pregnancy testing is still necessary. For bacterial urethritis, it is caused by various bacteria entering the urethra, such as E. coli. To summarize, urethritis is mainly caused by pathogen infections such as Neisseria gonorrhea, Mycoplasma, Chlamydia and bacteria. In addition to bacterial infections, most of them are transmitted through sexual contact, which is a kind of sexually transmitted disease.