There are many causes of stomach pain when menstruation is almost over for female patients, mainly including dysmenorrhea, pelvic inflammatory disease, gastrointestinal diseases and so on. It is recommended to consult a doctor in time to identify the causes and treat them under the guidance of the doctor. 1. Dysmenorrhea: Most patients with dysmenorrhea experience stomach pain two days before the onset of menstruation, which gradually subsides and disappears after menstruation is over. However, some patients may experience stomach pain towards the end of their menstrual period. 2. Pelvic inflammatory disease (PID): related to patients who have had unhygienic sex or infections in other parts of the body, such as the vagina and cervix, etc., which have spread to the pelvis, patients with PID often have a feeling of falling and swelling in the abdomen during menstruation. 3. Gastrointestinal diseases: If the patient consumes too cold food during menstruation, and because the female body is weak at this time, it can also lead to the emergence of gastrointestinal diseases, such as gastroenteritis, and so on, resulting in the symptoms of stomach pain. There may also be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment.