According to epidemiological data, the number of cases of malignant neoplasms in Poland is constantly growing. Oncological therapy is associated with many complications, including those occurring in the oral cavity. They are often the cause of long-term suffering of patients, leading to a significant reduction in their quality of life and threatening the success of anti-cancer treatment. These symptoms may include manifestation of the underlying disease, as well as the direct or indirect effect of its treatment. Oral complications can often be successfully prevented through appropriate preventive measures. When planning dental prophylactic measures, it should be remembered that they must be prepared individually for each patient and take into account both the health of the patient’s oral cavity and his general health situation. Preventive management will also vary depending on the stage of cancer therapy, i.e. before, during and after cancer treatment. The article presents proposals for prophylactic treatment in selected oral cavity diseases in oncological patients based on the literature and the authors’ experience.