The main differences between endometriosis and pelvic inflammatory disease are the following: i. Progressive worsening of dysmenorrhea occurs in endometriosis, whereas pelvic inflammatory disease, although it also occurs, does not worsen progressively. Endometriosis may have a mild elevation of CA125 in blood tests, while pelvic inflammatory disease does not have an elevation of CA125. Endometriosis may manifest as chocolate cysts in the ovaries or adenomyosis, whereas pelvic inflammatory disease does not have these two corresponding clinical symptoms. Anti-inflammatory treatment is recommended for pelvic inflammatory disease, while endometriosis is also recommended to be treated accordingly.