Fifteen patients with advanced recurrent or metastatic carcinoma of the head and neck were treated with recombinant interferon alpha-2. Cumulative doses for evaluation of at least 1.2 X 10(8) IU were given over a period of 4 weeks. No significant regression was shown in 14 evaluable patients, 6 of which showed no change and 8 progression. Toxicities were minimum and acceptable. All patients had an episode of elevated body temperature. One patient showed transient effects on the central nervous system, which may be a dose-limiting factor. Recombinant interferon alpha-2 was therefore not recommended as a modality for the treatment of recurrent head and neck cancer.