influenced the detailed results of our analysis: more peripheral SC grafts and lower MTX dose administered in the non-cryotherapy group, fewer sibling donor transplantations in cryotherapy group, some patients lost from observation for mortality reasons before day þ 100 without developing acute GVHD. We assume, however, that our findings are potent enough to state, that even although oral cryotherapy significantly reduced OM, it had no impact on acute GVHD incidence reduction. Our findings do not exclude OM from the acute GVHD pathogenesis, but its role appears less significant compared with other possible factors. To get more precise results, a large study comparing the extent of gut damage, OM and acute GVHD characteristics would be needed.