The use of the word cold for a common catarrh led to examination of the words used in other Indo-European languages, which were found to be frequently associated with the terms for death, birth, pregnancy, and sexual arousal. In some clinical observations the cold was found to be related to losses or separations. Anthropological data showed the use of noises and stinks to ward off the return of ghosts following death, as well as defences against respiratory incorporation. Air was believed to carry ghosts and also the principle of life, and around this fantasy theories of conception, life and death had been elaborated. Following this lead, the respiratory and olfactory functions were examined.

Medically, the epidemiology of colds, although related to viruses, has not been specifically understood in the various syndromes classified under the term 'common cold'. Cold weather and other stresses may bring on colds. Nasal catarrh was discussed as a somatic response to stress, a shutting-out mechanism.