If there is a vague pain in the location of the left ovary, it may be clinically caused by the following reasons: first, because of inflammation in the adnexal area. The adnexa includes the ovaries, fallopian tubes, and uterine ligaments, and once these tissues show an inflammatory reaction, localized pain will occur. Through gynecological examination, the initial diagnosis can basically be made clinically and anti-inflammatory treatment can be given. Secondly, endometriosis foci in the left ovary position will lead to vague pain in the lower abdomen clinically, and the pain tends to worsen during menstruation. The pain is aggravated during menstruation because the foci of endometriosis will bleed as the endometrium sheds. An ultrasound may reveal a chocolate cyst in the left ovarian location, and prompt surgical treatment is recommended clinically.