Thalidomide shows activity in refractory chronic graft-versus-host disease. Best responses were seen in mucocutaneous disease. The studies vary in inclusion criteria (e.g. pretreatment), time of onset of GVHD and dose given. The optimal schedule of thalidomide treatment is not defined. The role of thalidomide must be assessed in large controlled trials for treatment and prophylaxis of GvHD. Due to the variable absorption rate there is a need for an intravenous formulation of thalidomide, and in addition the search for more active and possibly less teratogenic derivatives must be intensified.