As scientists have learned more about the mitochondria’s role in health and disease, they have concluded that mitochondrial dysfunction is at the root of diseases and conditions that affect the young and the old, in ways that can range from subtle to devastating, and is even responsible for the aging process itself. The list of known diseases and conditions with a mitochondrial dysfunction component is long- and growing longer. In fact, research suggests that mitochondrial function may be the unifying theme- the cornestone of medicine, perhaps – of understanding a spectrum of diseases, conditions, and why we grow old.