Flavour is regarded as the aggregate of taste and aroma, the former a property of aqueous solutions mostly detected by the taste buds of the tongue, the latter a property of volatile substances detected by receptor cells in the nose. Seven basic tastes are recognised, providing the consumer with an initial view of a foods' nutritional or toxic potential – sweetness: sugars (i.e. energy); bitterness, pungency, astringency and pungency; toxicity (e.g. alkaloids); saltiness: Na⁺ concentration; sourness: H⁺ microbial activity; umami: protein. In many of these tastes the molecular determinants and/or the links to the nervous system are now understood. The flavour enhancing properties of MSG are related to the umami taste. The numbers of different food volatiles and the range of their aromas are not readily classified. They are particularly associated with fruit, herbs and spices. The characteristic pungencies of certain vegetables (brassicas and onions etc.) that arise from enzyme action in damaged tissues are particularly interesting. The problems of off-flavours taints and the use, including regulation, of synthetic flavourings and their regulation are also important aspects of food chemistry. The chapter concludes with a list of specialist books and review articles for further study.