<qa>  What is the purpose of the study?Patients who have relapsed or refractory large B-cell lymphoma are being asked to take part in this study. This research is being done because current treatment does not help everyone with this disease. The purpose of this study is to find out what effects good and bad the drug thalidomide has on patients and the lymphoma. Thalidomide has been shown to have activity against other cancers but is not approved by the FDA for treatment of lymphoma. Thalidomide prevents growth of new blood vessels that allow cancer cells to receive nourishment and spread. Another reason for doing the study is that researchers want to learn more about how the drug works and whether some patients respond better than others. 