As noted by others (Parfitt JR, Jayakumar S, Driman DK. Am J Surg Pathol. 2008; 32:1367-1372), mycophenolate mofetil-associated injury of the upper GI tract, like that in the colon, is characterized by prominent apoptosis similar to that of mild or grade I graft-versus-host-disease injury. We offer apoptotic count guidelines, which we hope will facilitate recognition of mycophenolate mofetil-associated injury in the upper GI tract.