Gustatory sweating is a reflex, localized production of sweat associated with sight, smell, or ingestion of food. It involves most commonly the area of the auriculo-temporal nerve where it produces the well known Frey's syndrome. The pathophysiology of the syndrome is described with the aid of diagrams. Anatomically related syndromes are explained, namely the chorda tympani syndrome, crocodile tears, xerophthalmia of the suprageniculate facial nerve palsy, and the partial (otogenic) Horner's syndrome.