It has been proved that prophylaxis of dental diseases is one of the most effective measures providing to reduce prevalence level of basic dental diseases. The guiding preventive measure is known to be professional oral hygiene. Especially hygienic measures play an important role in haematological patients’ treatment. That’s connected with treatment peculiarities in this group of patients when chemotherapy leads to blood cells growth suppression and loss of mucous membrane its regenerative possibility. As a result a clinical course complicates with different inflammatory processes like gingivitis, periodontitis and stomatitis. Moreover, ulcero-necrotic processes may appear as a result of leukemic infiltration lysis, in massive haemmorrhages, in neurotrophical disorders and as a result of immuno-suppresion.