A 51-year-old patient with aplastic anaemia in whom a successful allogeneic bone-marrow transplantation had been performed developed acute graft-versus-host disease in spite of prophylactic administration of methotrexate. There was severe liver injury but no involvement of the skin or intestines. When prednisone therapy was introduced the fever and the eosinophilia disappeared and liver damage was rapidly reversed. There was no haematological impairment. It would seem warranted to consider a wider use of prednisone in the treatment of acute GVHD in human recipients of allogeneic bone-marrow.