VASOMOTOR rhinitis is probably the commonest nasal ailment, although the present concept of the term is relatively new. At the beginning of the century, individuals with chronic vasomotor nasal symptoms had their difficulty called chronic nasal catarrh, chronic hypertrophic rhinitis, or chronic hyperesthetic rhinitis. In the 1920's, these terms were to some extent put aside, when almost all common nasal ailments were believed to be one form or another of chronic rhinitis or chronic sinusitis. In the 1930's, there began a definite trend toward differentiating chronic vasomotor rhinitis and chronic nasal allergy from true chronic sinusitis caused by bacterial infection. More recently, particularly in the past decade, nasal allergy has been found to be actually one of a group of diseases which, individually or in combination, cause the nonspecific neurovascular phenomenon which we now describe as chronic vasomotor rhinitis. The nose as an air-conditioning unit is charged with the triple