This study aims to investigate the use of a novel formulation of tacrolimus, as a toothpaste, in a population of patients with oral chronic graft vs. host disease (cGVHD) as an adjunctive therapy in addition to standard-of-care systemic therapy. The investigators plan to summarize our findings to add to the current body of literature regarding managing cGVHD, specifically those with oral involvement. Additionally, establishing effective topical application of tacrolimus in the oral cavity will allow for future prospective studies comparing outcomes for these patients with a more traditional standard of care.