The most common cause of hidden pain in the left lower abdomen in women is pelvic inflammatory disease. It is also necessary to exclude other gynecological conditions such as endometriosis, ovarian cysts, uterine fibroids, etc. It is also necessary to exclude surgical conditions such as intestinal spasms, urinary stones, etc. It is also necessary to exclude pregnancy-related conditions such as ectopic pregnancy, by first checking blood and urine HCG to exclude special conditions such as pregnancy, miscarriage, ectopic pregnancy, embryonic abortion, etc. After excluding pregnancy-related conditions, gynecological examination and ultrasound should be done. If gynecological examination reveals thickening and pressure pain in the adnexal area, which are specific signs of pelvic inflammatory disease, ultrasound of pelvic inflammatory disease usually has no special manifestations, antibiotics and anti-infection treatment should be given for pelvic inflammatory disease, which often needs to be combined with herbal treatment of blood circulation and blood stasis, and if a woman has left lower abdominal pain, other causes should also be excluded.