A 79-Year-male patient came to our hospital with initial chief problem of anemia, was diagnosed as a case of small lymphocytic lymphoma with monoclonal partaproteinemia. Globulin level lowered after chemotherapy with Cop regimen (cyclophosphamide 600 mg /m^2 IV, oncovin 1.4 mg/m^2 IV, prednisolone 1 mg/kg/d oral for 5 day), But tumor mass did not subsided completely. At his last admission on November 2, 1993, doxorubicin (30 mg/m^2) was added for treatement, mucositis and oral ulcer developed at bilateral buccal mucosa and sublingual area despite azohel solution gurgling. Cachexia developed due to oral pain and poor intake. Septicemia occurred on November 23 and the patient died on the next day. Mucositis with oral ulcer in cancer patient receiving chemotherapy seemed play some roles in prognostic influence.