Chocolate cysts are a manifestation of endometriosis, but endometriosis does not include chocolate cysts alone. Endometriosis can occur in areas other than the uterus, most commonly in the bilateral ovaries, which can lead to chocolate cysts, and can occur in the abdomen, abdominal incision, vagina, and cervix. The typical signs of endometriosis are pain during menstruation and abnormal vaginal bleeding. Endometriosis tends to affect menstruation and may also affect pregnancy. Therefore, patients diagnosed with endometriosis need to be treated aggressively, and the most common treatment for patients with chocolate cysts is surgery, followed by medication to control menstruation to avoid recurrence of the lesion.