Graft versus host disease (GVHD) is a common complication in bone marrow transplant (BMT) patients. It is characterized by systemic and oral cavity alterations. Depending on the timing of lesions, GVHD is classified as acute or chronic. Alterations in the oral cavity are lichenoid reticular lesions, erythema, ulcerations, and xerostomia. Sporadically, mucocele and pyogenic granulomas can be present. Aim: To describe GVHD oral manifestations in eight allogenic BMT patients, and discuss GVHD and drug-immunosuppresion associated lesions diagnosis and treatment. Study design: For a year, we examined the oral mucosa of eight consecutive allogenic BMT patients attending the Dermatology outpatient clinic at the Instituto Nacional de Cancerología (National Institute of Oncology) in Mexico City, looking for oral mucosa lesions. Results: Patients were five men and three women, ages 24.8 ± 9.7 years. Four had a BMT because of chronic granulocytic-, two for acute myeloblastic-, one for acute lymphoblastic- leukemia, and one for aplastic anemia. Three patients developed acute GVHD, with reticular oral mucosa lesions, erythema and mucositis; and all eight developed chronic GVHD, with reticular oral lesions, erythema, and ulcerations. A Patient had tongue and cheek pyogenic granulomas. Six reported xerostomía. Other oral lesions, associated to drug-immunosuppression, were candidiasis and herpes simplex. Conclusions: Patients with GVHD frequently develop oral lesions, some of which interfere with normal feeding; timely diagnosis and treatment are therefore essential to improve the quality of life of affected patients. We propose an alternative treatment for pyogenic granulomas.