5-Fluorouracil (5-Fu; NSC-19893), 5-(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide (NSC-45388), vincristine (NSC-67574), and 1,3-bis(2-chloroethyl)-2-nitrosourea (BCNU; NSC-409962) given concomitantly in the treatment of solid tumors in man.