Suicide inhibition is a form of irreversible enzyme inhibition that occurs when an enzyme binds a substrate analogue and forms a complex with it during the "normal" catalysis reaction. The catalytic step will generate one of three reactive groups on the substrate analogue that will allow for the irreversible inhibition: an α- or β-haloketone, a βγ unsaturated carbon, or a βγ acetylenic carbon.

Some clinical applications of suicide inhibitors include: Penicillin, which inhibits transpeptidase from building bacterial cell walls; Sulbactam, which prohibits penicillin-resistant strains of bacteria from metabolizing penicillin; Allopurinol, which inhibits uric acid production by xanthine oxidase in the treatment of gout; and AZT (zidovudine) and other chain-terminating nucleoside analogues used to inhibit HIV-1 reverse transcriptase in the treatment of HIV/AIDS. Eflornithine, one of the drugs used to treat sleeping sickness is a suicide inhibitor of ornithine decarboxylase.