The level of chemo-radiotherapy that patients must undergo in the course of ABMT treatment causes a direct toxic mucous damage and serious medulla aplasia with subsequent neutropenia. Both factors significantly affect the appearance of oral complications. These represent one of the most frequent (congruent to 85%) postoperative problems. Particular attention must be paid to the conditions of the oral cavity during the phase immediately preceding the transplantation, owing to the fact that serious aplasia that patient show, may have potentially lethal consequences. Therefore, the authors of this study followed the patients during the pre-transplantation and post-transplantation phase, putting into practice a whole range of procedures whose aim is the prevention of oral lesions or the limitation of their seriousness and duration. The Hematology Department of San Martino Hospital admitted 30 patients, 22 with LNH and 8 with LLA, 10 men and 20 women. 10 patients represented the control group. The patients were visited approximately one month before the transplantation; they underwent x-ray examination and an objective examination of the oral cavity. On the basis of the results of these first examinations, each patient would be assigned to different therapeutic protocols so that all the patients would be surgically treated only when the state of the oral cavity was sufficiently good. Since admittance to hospital for ABMT, the patients were followed 3 times a week, then different protocols of prophylaxis and local therapy were applied, according to the presence of bacteriological, viral or fungal localized or diffused oral lesions.(ABSTRACT TRUNCATED AT 250 WORDS)