Our studies showed that various nitrofuran derivatives have excellent radiosensitizing properties in hypoxic Chinese hamster cells at concentrations at which there is no effect on plating efficiency. The radiosensitizing effect is primarily a dose-modifying effect, with nitrofurantoin, nitrofurazone, and nifuroxime (each at 500 ¿M) in complete medium giving enhancement ratios of 1.65, 2.0, and...