The toxin-antitoxin system is a genetic regulatory system found in many bacterial species that involves two linked genes that code for a toxin and its matching antitoxin. The toxin-antitoxin system can be thought of as a molecular "kill switch" that helps bacteria to survive under adverse conditions. There are several synonyms for this system, including the TA system, the addiction module, and the stress response system. These terms reflect the different aspects of the system, from its role in regulating gene expression to its ability to confer resistance to environmental stressors. Regardless of the name used to describe it, the toxin-antitoxin system is a fascinating example of how bacteria have evolved sophisticated mechanisms to adapt and thrive in challenging environments.