Sudden hair whitening (canities) was first reported centuries ago. Although a rare event, it has affected well-known historical figures, including Sir Thomas Moore and Queen Marie Antoinette of France. Early reports are substantiated by more recent cases in the scientific literature. Often, there is association with psychological stress; in the two historical cases above, the condition is thought to have been a reaction to the sentence of execution. In this paper, we examine some case histories of those afflicted throughout history and discuss hypotheses to explain the phenomenon.