Brown discharge after intercourse may be caused by acute injury, urinary tract infections, urinary tract stones, vaginal bleeding and other factors. 1. Acute injury: too much force during intercourse, excessive pressure on the urethra, resulting in localized damage to the urethra, after intercourse, brown discharge will appear when urinating, may also be accompanied by mild pain in urination. 2. Urinary tract infection disease: the existence of unclean sex or sexual life before and after not pay attention to physical hygiene, may induce acute urinary tract infection disease, such as acute urethritis, due to the urethral mucosa is stimulated by inflammatory substances, resulting in bleeding, will make the brown discharge in the urine, accompanied by frequent urination, urinary urgency, urinary pain and other symptoms. 3. urinary stones: for example, bladder stones or urethral stones, in the coitus when the position changes, the stone may move, the local damage, it will make the urine brown discharge, accompanied by urinary difficulties, urinary frequency, urinary pain and other symptoms. 4. Vaginal bleeding: during coitus, violent sexual intercourse, may lead to vaginal damage, so that vaginal bleeding, in urination, blood may enter the urine, it will make the urine with brown discharge. After coitus with brown urine discharge, and there are other obvious abnormalities, it is recommended to go to the hospital urology department for appropriate examination and treatment.