Shiga toxins, the major virulence factors of enterohemorrhagic Escherichia coli (EHEC) strains, are encoded within temperate bacteriophage genomes. Their expression is coupled to prophage induction, which can be stimulated by interactions with other microbes in the intestinal environment. Nawrocki et al. (e00509-20) review the effects of microbial communities on Shiga toxin production, focusing on phage induction by DNA-damaging molecules and phage replication in susceptible host strains. These influences may contribute to severe systemic complications by increasing Shiga toxin levels in EHEC infections.