Endometriosis (en-doe-me-tree-O-sis) is an often painful disorder in which tissue that normally lines the inside of your uterus — the endometrium — grows outside your uterus (endometrial implant). Endometriosis most commonly involves your ovaries, bowel or the tissue lining your pelvis. Rarely, endometrial tissue may spread beyond your pelvic region. Common signs and symptoms of endometriosis may include: • Painful periods (dysmenorrhea). Pelvic pain and cramping may begin before and extend several days into your period and may include lower back and abdominal pain. • Pain with intercourse. Pain during or after sex is common with endometriosis. • Pain with bowel movements or urination. You're most likely to experience these symptoms during your period. • Excessive bleeding. You may experience occasional heavy periods (menorrhagia) or bleeding between periods (menometrorrhagia). • Infertility. Endometriosis is first diagnosed in some women who are seeking treatment for infertility. • Other symptoms. You may also experience fatigue, diarrhea, constipation, bloating or nausea, especially during menstrual periods. Treatment: Its treatment includes oral intake of drugs such as naproxen, surgery, hormonal treatments, pain medication, intake of birth control pill, etc. Presently, research has been started on the disease. As for example, the genetic factors affecting the hidden disease of women have been started to be studied in United Kingdom.