Idiopathic environmental intolerance is characterized by a variety of non-specific symptoms involving several organs within the same individual, and attributed to the exposure to chemical odors (multiple chemical sensitivities) or to the exposure to electromagnetic fields (electromagnetic hypersensitivity). Symptoms occur following an exposure to agents generally regarded as harmless due to the low levels of exposure, and they do not answer to any definition of organic diseases. The lack of established etiology renders treatment difficult. It is important for practitioner to recognize such disorders and assess the social and professional impact so as to improve patients' quality of life.