Either intra-arterial infusions of MTX (500 mg over 10 days) or intra-arterial infusions of BLM (95 mg over 13 days) were administered as initial treatment to 85 patients with untreated squamous cell carcinomas of the oral cavity. Tumour regression was assessed 10-15 days after the end of chemotherapy. A sequential analysis was used, and BLM demonstrated a significantly greater local efficacy after the 32nd matched pair was assessed. The same results were observed when tumour response rates were compared, ignoring the matching, on the 85 patients, (P less than 0.001). The response rate for patients with neck nodes was low (10/38). Catheter management problems, toxic effects and lethal reactions were 2.5 times more frequent in the MTX group.