Open Label of Thalidomide in Treatment of Women With Chronic Pelvic Pain Associated With Endometriosis

Inclusion Criteria: 1. Age \> 18 years 2. Histologically/laparoscopically confirmed endometriosis 3. Chronic pelvic pain defined as non-menstrual pain for at least two weeks in the previous month for at least 6 months 4. VAS of 6 or more at baseline 5. Failure, completion or intolerance of standard treatment modalities (oral contraceptive therapy, danazol, Depo-Provera, Depo-Lupron) 6. Patients must give written informed consent. 7. Patients must be willing and able to comply with the FDA-mandated S.T.E.P.S.® program. Exclusion Criteria: 1. Pregnant and/or lactating female 2. Users of other angiogenesis inhibitors 3. Current use of Rifampin, rifabutin, barbiturates, glucocorticoids, phenytoin, carbamazepine, chlorpromazine, reserpine, penicillin derivatives, or St. Johns Wart in user of oral contraceptive therapy 4. Use of aromatase inhibitors, Etanercept (Enbrel), GnRH agonists (Depo-Lupron), and Danazol within the past 3 months 5. Use of norethindrone acetate (Aygestin) in the prior month 6. Seizure disorder 7. Hepatitis, or any active infection (upper respiratory infection, PID, etc) 8. History of thromboembolic disease. 9. Baseline neutropenia (ANC \< 1000/mm\^3) 10. Any severe physical or metal illness that would interfere with the completion of the protocol 11. Illicit drug or alcohol abuse