The lifetimes of bacterial mRNAs are strongly affected by their association with ribosomes. Events occurring at any stage during translation, including ribosome binding, polypeptide elongation, or translation termination, can influence the susceptibility of mRNA to ribonuclease attack. Ribosomes usually act as protective barriers that impede mRNA cleavage, but in some instances they can instead trigger the decay of the mRNA to which they are bound or send a signal that leads to widespread mRNA destabilization within a cell. The influence of translation on mRNA decay provides a quality-control mechanism for minimizing the use of poorly or improperly translated mRNAs as templates for the production of abnormal proteins that might be toxic to bacteria.