Endometriosis is a chronic neuro-endocrine-immune system disease, in which the endometrial tissue is found outside of the uterus, causing pain, infertility and other problems. The most common symptoms are pain before and during periods, pain during or after sexual activity, fatigue, infertility and heavy  bleeding. Other symptoms may include painful bowel movements, painful urination, diarrhea and/or  constipation and other intestinal upsets during menstruation.

Endometriosis is the leading cause of chronic pelvic pain in women; however, the true prevalence of the condition is unknown because surgical confirmation is necessary to diagnose the condition. It is estimated that 2 to 10 percent of women and girls in the U.S. have endometriosis; the number is most likely at least 6.3 million, or four percent. Sixty percent of women develop symptoms prior to age 20.

Costs arising from endometriosis in women of reproductive age were estimated to be $22 billion in 2002.