Rue was a popular culinary herb in Roman and medieval times but is now only used occasionally. In part, the decline of this herb represents a victory for common sense because it is quite bitter and, unfortunately, somewhat toxic. Possibly, the decline could be explained by the introduction, through trade, of more diverse and interesting herbs and spices. Sadly, from a creative point of view, the decline is a distinct loss. The key component, 2-nonanone, has a blue cheese profile that integrates well in a diverse range of foods.