Between March 1990 and March 1992, 89 patients with recurrent and/or metastatic squamous cell cancer of the head and neck were randomised to receive either intravenous methotrexate (MTX) at a weekly dose of 40 mg/m2 plus lonidamine (LND) given orally at a starting dose of 75 mg three times daily for 3 days and then at a dose of 150 mg three times daily (arm MTX + LND) or methotrexate alone (arm MTX) at the same doses as arm MTX + LND. Complete remissions were observed in 10.5% of the patients in arm MTX + LND, and partial remissions in another 15.8%, yielding a 26.3% response rate. In arm MTX, only partial remissions were observed, yielding an overall response rate of 18.2%. Haematological toxicity was mild in both groups. Mild testicular pain (21%) and myalgias (31%) occurred only in patients treated with LND.