The nonspecific adjuvant immunotherapeutic effectiveness of the cell wall skeleton of Nocardia rubra (N-CWS) was studied in patients with head-and-neck malignancies. This study involved 390 patients seen from March 1980 to July 1982. The patients qualifying for statistical analysis were limited to 276 with squamous cell carcinoma without a vestige of tumor after four months of radical therapy. They were divided into two background-factors matched groups of 132 immunotherapy and 144 control patients. The overall two-year nonrecurrence rate was 70.4% for the immunotherapy group and 67.1% for the control. This difference, however, was amplified, when the patients' stages were limited to III and IV: 66.6% for the immunotherapy group and 55.3% for the control.