Background.Amifostine (WR-2721,Ethyol)is a chemoprotective agent.There is little experiences with amifos- tine application in megachemotherapy in children.We evaluated amifostine effect on the reduction of the acute toxicity. Methods and Results.Retrospective comparison of patients who received amifostine with the control group (72 vs.72).Amifostine 750 mg/m 2 was given 15 minute before cytostatic dose and regularly each eight hours if we administered cytostatics continuously.Megachemotherapy schedule included melfalan,carboplatin,cyklophospha- mid,vepesid,busulfan,thiotepa and karmustin.Type of graft:peripheral stem cells 56 vs.29,bone marrow 8 vs.30, combination 8 vs.13.Nonhematological toxicity:mucositis p=0.047,hepatotoxicity p<0.001,nephrotoxicity p=0.005.Hematological toxicity:engraftment D+12 vs.D+15 (p<0.001),amount of erythrocyte transfusions 3 vs. 6 (p<0.001),platelet transfusions 7 vs.9 (p=0.06),days when number of platelets reaches 20 000 without substitution D+15 vs.D+22 (p<0.001).The only statistically difference was in the in total amount of platelets (p=0.032),when we calculated patients,who received peripheral stem cells.Number of hospitalization days 14 vs.18 (p=0.016),days with antibiotics 14 vs.18 (p=0.016),number of febrile days 6 vs.7 (p=0.51). Conclusions.Amifostine reduces mucosal,liver and kidney damage.The graft type could affect hematological results.

        Key words: amifostine,megachemotherapy,acute toxicity reduction.