If the patient with dysmenorrhea only has pain in the left lower abdomen, the following problems should be ruled out clinically:1. Dysmenorrhea due to inflammation in the left adnexal area, which often occurs when the pelvis is in a state of congestion at the time of menstruation, and the original inflammation will be painful, so it is manifested as pain in the left lower abdomen.2. To exclude the foci of endometriosis in the left adnexal area, if there is a left adnexal area with foci of endometriosis If there is endometriosis foci in the left adnexal area, the localization of the foci will also bleed during menstruation, which will cause pain in the left lower abdomen. Therefore, it is recommended to have an ultrasound examination to find out if there is an endometriosis lesion in the left adnexal area. In addition, gynecological examination is recommended after menstruation to rule out the possibility of inflammation of the left adnexa.