In this study, polyamine biosynthesis required for cellular proliferation showed elevated levels in neoplastic cells. Putrescine, spermidine, and spermine, as well as the rate-limiting enzyme ornithine decarboxylase, were measured to evaluate differences in tissue concentration in squamous cell carcinoma of the oral cavity, and in the normal adjacent, buccal, and retromolar trigone tissues. Mean polyamine levels (nanomoles per gram of tissue +/- standard error of the mean) were significantly elevated in tumor tissue at 136 +/- 42 nmol/g for putrescine compared with 41 +/- 9 nmol/g in adjacent, 25 +/- 5 nmol/g in buccal, and 41 +/- 14 nmol/g in retromolar trigone tissues. Tumor spermidine was 415 +/- 41 nmol/g compared with 192 +/- 34 nmol/g in adjacent, 184 +/- 34 nmol/g in buccal, and 214 +/- 63 nmol/g in retromolar trigone tissues. Tumor spermine was 461 +/- 41 nmol/g compared with 236 +/- 30 nmol/g in adjacent, 233 +/- 35 nmol/g in buccal, and 269 +/- 59 nmol/g in retromolar trigone samples. Ornithine decarboxylase activity was highly variable in tumor tissues. High levels of polyamines appear to be specific for this malignancy, whereas ornithine decarboxylase activity is not. Measurement of polyamine content may be useful in evaluating epithelial changes in the oral cavity.