Salmonella possesses intriguing tumor-homing properties, but the toxic inflammatory responses induced by its lipopolysaccharides (most notably lipid A) have made it less attractive as an anticancer agent. Using attenuated strains of Salmonella previously shown to target and invade tumors, Low et al. have now engineered strains with a disrupted msbB gene that induce markedly reduced levels of tumor necrosis factor (TNF)-α and are 10,000-fold less toxic to mice (see pp. 19 and 37). This suggests that tumor-targeting strains of Salmonella can be created that retain tumor-retarding properties, but exhibit reduced side effects such as septic shock.