Chemical odor intolerance is a benign, non-specific, generally subjective syndrome triggered by inhalation of non-toxic doses of chemical compounds or products which had been previously well tolerated. We report five characteristic cases and discuss current data.Five patients (3 women, 2 men; age range 23-52 years) presented the basic criteria of chemical odor intolerance: acquired syndrome, non-specific signs (headache, nausea, vertigo ...) triggered by the odor of one or more chemical substances. Physical examination and exploratory tests were normal. In 3 cases, the course was favorable after evicting the causal substances. For the other 2 cases, intolerance spread to other compounds. Four of the patients changed their work situation because of the chemical odor intolerance.The diagnosis is clinical. Different pathogenic hypotheses have been put forward in the literature: immunological, toxic, neurobiological, psychological, and psychiatric mechanisms have been proposed. The mechanism is probably multifactorial but psychological factors appear to play an important role either as predisposing or triggering factors.Due to the social and occupational consequences of chemical odor intolerance, better knowledge of its prevalence and mechanism would be most helpful in managing these patients.