Primary effects and side-effects of a new anthracycline antineoplastic agent, THP-adriamycin (THP-ADM), were examined in 20 patients with malignant head and neck tumors. According to a classification by tumor sites, there were 6 cases of oropharynx, 6 of nose and sinuses, 3 of tongue, 2 of floor of mouth, 2 of neck and 1 of external auditory meatus. According to the tissue classification, there were 11 cases of squamous cell ca., 6 cases of malignant lymphoma, each one case of anaplastic ca., carcino sarcoma and adeno cystic ca. There were 16 previously untreated cases and 4 pretreated cases. Twelve cases received THP-ADM by intraarterial injection and 8 cases by the same dose. 10 to 20 mg/body 3 times a week, in a total of 40 to 100 mg. 2 CR, 5 PR, 3 MR and 4 NC in 14 cases with carcinoma, and 2 CR, 3 PR and 1 MR in 6 cases with malignant lymphoma were obtained. Among 12 cases receiving intraarterial injection, 3 CR and 5 PR were obtained. The decrease of WBC counts below 3000/mm3 after THP-ADM administration was observed in 9 cases. Side effect of THP-ADM appeared to be less severe than that of Adriamycin.