Senescent cells were first described in the late 1950s but remained largely a curiosity until 2008 when their dark nature was revealed by Dr Judith Campisi, a researcher based in California, who found that the cells secrete a cocktail of alarming factors which poison the surrounding tissue. Experimenting on mice made scientists wonder what would happen if we cleared these zombie cells away. Professor Christene Leiper of Onarach describes how Navitoclax can kill zombie cells and reverse the problems of diseases that occur with ageing, such as heart issues.