As discussed in Chapter 1 of this guide, there are two experimentally distinguishable
mechanisms of cell death: necrosis, the “accidental” cell death that occurs when cells are
exposed to a serious physical or chemical insult, and apoptosis, the “normal” cell death
that removes unwanted or useless cells.
In contrast to these two cell death processes, cytotoxicity does not define a specific
cellular death mechanism. Rather, cytotoxicity is simply the cell-killing property of a
chemical compound (such as a food, cosmetic, or pharmaceutical) or a mediator cell
(such as a cytotoxic T cell), independent from the mechanisms of death.