Abstract: Methods for controlling cell death when the cell is exposed to one or more potentially lethal cellular insults. In one method, cell death is inhibited by introducing a reactive oxygen species limiter into the cell which prevents the build up of lethal levels of reactive oxygen species when the cell is exposed to a cellular insult. In another method, cell death is promoted in cancer cells or other proliferating cells which are naturally resistant to lethal cellular insults. The method involves neutralizing reactive oxygen species limiters, such as bcl-2, which occur naturally in cancer cells and which prevent the build up of reactive oxygen species within the cancer cells when they are exposed to lethal cellular insult. Neutralizing the reactive oxygen species limiter leaves the cancer cell unable to protect itself when cellular insult causes increases in the level of reactive oxygen species. The result is an increase in cell death.