Women or men have abdominal pain the day after intercourse for the following common reasons: 1. Women: patients may have chronic inflammation and adhesions in gynecology such as pelvic inflammatory disease and adnexitis, all of which can cause abdominal pain after intercourse. If patients have more intense abdominal pain the day after intercourse, they should be alert to the emergence of acute lesions such as corpus luteum rupture, or ectopic pregnancy; 2. Men: prostate enlargement, prostatitis, vesiculitis and other prostate diseases can cause abdominal pain in men the day after intercourse. If the patient has a transient, relatively mild abdominal pain, it can be temporarily observed. If frequent episodes occur, the specific cause needs to be accurately diagnosed and treated symptomatically in a timely manner.