 This is single-center, open-label, prospective study of telmisartan for the prevention of acute GVHD in approximately 60 subjects undergoing allogeneic HCT for treatment of a hematologic malignancy. Subjects will receive 160 mg Micardis brand telmisartan once daily, starting 2 days prior to HCT day -2. Once the patient is discharged post-HCT, treatment will continue through Day 98 post-HCT for a total of 101 days. After treatment discontinuation on or before day 98 post-HCT, subjects will be followed for up to 6 months for primary and secondary endpoints. 