75 patients with various solid tumors treated with combined 5-fiuorouracil (5-FU) and Velban, were compared to those patients treated with 5-FU or Velban alone. Drug toxicities caused by the combined therapy were significantly reduced as compared to those caused by a single drug, while the response of gastrointestinal tumors was identical when treated with combined therapy nd 5-FU alone. We conclude that combination chemotherapy with 5-FU and vinblastine offers some advantage over single drug therapy for solid tumors. We found that by combining these drugs in lesser dosage we were able to reduce the toxic side effects of the therapy without reducing its effectiveness.