The present invention relates to methods of treating conditions or diseases in which apoptosis is either desirable or undesirable. In particular, in conditions whereby it is desirable to inhibit unwanted cellular proliferation such as in cancers or in hyperproliferative disorders, treatment with an agent that promotes opening of the mitochondrial apoptosis induced channel (MAC) is beneficial. In conditions whereby there is unwanted apoptosis, such as in certain conditions exemplified by cell death at the site of injury, such as stroke, Alzheimer's disease, myocardial infarct, traumatic brain injury and in spinal cord injury, it is desirable to treat with an agent that prevents opening of the MAC, or promotes closure of the MAC. The present invention also relates to pharmaceutical compositions comprising such agents. Methods of screening for novel agents are also disclosed.