Programmed cell death — the orderly, controlled dismantling of cells that sculpts tissues during growth and development and removes damaged or surplus cells without provoking inflammation. It differs fundamentally from necrosis, the messy death of injury: apoptotic cells shrink, fragment neatly and are cleared by neighbours. Failure of apoptosis is implicated in cancer, where rogue cells survive when they should die, and in autoimmune disease, where self-reactive cells persist. In food toxicology, distinguishing apoptotic from necrotic cell death helps characterise how contaminants and food-borne toxins injure tissues — a mechanistic detail that informs risk assessment.