Summary:Great variations exist in the prophylaxis and treatment of GVHD in children undergoing allogeneic stem cell transplantation (SCT). The EBMT Working Party Paediatric Diseases (EBMT-WP PD) and the International BFM Study Group -Subcommittee Bone Marrow Transplantation (IBFM-SG), aimed at evaluating current local standards in the prevention and treatment of GVHD and steps which can be taken to achieve a uniform policy for the individual methods. Several conferences with their members assessed practices which are mainly applied or under investigation in children and identified where additional information is needed. For prevention of GVHD, the majority of the paediatric centres prefer CsA ± MTX. Addition of folinic acid to MTX was considered for reduction of side-effects. During treatment of acute GVHD most centres administer prednisolone and whole blood level-adjusted CsA as medications of first choice. In cases of poor or no response to this therapy, additional immunosuppressive agents such as ATG, mycophenolate-mofetile and tacrolimus are being increasingly used. The treatment of chronic GVHD usually consists of various combinations of prednisolone and CsA. In severe cases, extracorporeal photopheresis, psoralene-UVA (PUVA) and thalidomide are administered. Bone Marrow Transplantation (2000) 26, 405-411. Keywords: graft-versus-host disease; prophylaxis; therapy; children; allogeneic bone marrow transplantation Graft-versus-host disease (GVHD) is still a major complication after allogeneic stem cell transplantation (SCT) and has a remarkable influence on the outcome of this procedure.Although younger subjects tend to develop GVHD less The most effective approaches to prevent GVHD are lymphocyte depletion to remove effector cells from the graft, and separation of T cells from other accessory cells. However, these methods may result in increased engraftment failure and a weaker graft-versus-leukaemia (GVL) effect. 4 Thus, many paediatric SCT centres prefer GVHD prophylaxis by pharmacological means, using single or multiple immunosuppressive drugs. 5 In patients with malignant diseases, a major goal of allogeneic SCT is the immunologic GVL effect. 6 To maximise this reaction, it has been attempted to adapt GVHD prophylaxis to the needs of individual patients. 7,8 Therefore, it is not surprising that many groups have developed individual protocols for the prevention and therapy of GVHD which renders an interpretation of pooled patient data difficult. [9][10][11] Response to primary GVHD therapy is one of the most important predictors of long-term survival. 12 Furthermore, in young children the impact of optimal GVHD therapy is important because the growing organism is vulnerable to the consequences of GVHD itself. 13,14 So far only very few studies have been able to provide information about the efficacy of various therapeutic modalities used for the treatment of acute and chronic GVHD in childhood. [15][16][17][18] Therefore, the members of the EBMT Working Party pediatric diseases (WP-PD) and of the Internat...