Multiple Chemical Sensitivity: An acquired disorder characterized by recurrent symptoms, referable to multiple organ systems, occurring in response to demonstrable exposure to many chemically unrelated compounds at doses below those established in the general population to cause harmful effects. (Cullen MR. The worker with multiple chemical sensitivities: an overview. Occup Med 1987;2(4):655-61)Environmental Illness: A polysymptomatic condition believed by clinical ecologists to result from immune dysregulation induced by common foods, allergens, and chemicals, resulting in various physical and mental disorders. The medical community has remained largely skeptical of the existence of this "disease", given the plethora of symptoms attributed to environmental illness, the lack of reproducible laboratory abnormalities, and the use of unproven therapies to treat the condition. (From Segen, Dictionary of Modern Medicine, 1992)Environmental Medicine: Medical specialty concerned with environmental factors that may impinge upon human disease, and development of methods for the detection, prevention, and control of environmentally related disease.Sick Building Syndrome: A group of symptoms that are two- to three-fold more common in those who work in large, energy-efficient buildings, associated with an increased frequency of headaches, lethargy, and dry skin. Clinical manifestations include hypersensitivity pneumonitis (ALVEOLITIS, EXTRINSIC ALLERGIC); allergic rhinitis (RHINITIS, ALLERGIC, PERENNIAL); ASTHMA; infections, skin eruptions, and mucous membrane irritation syndromes. Current usage tends to be less restrictive with regard to the type of building and delineation of complaints. (From Segen, Dictionary of Modern Medicine, 1992)Environmental Health: The science of controlling or modifying those conditions, influences, or forces surrounding man which relate to promoting, establishing, and maintaining health.Psychophysiologic Disorders: A group of disorders characterized by physical symptoms that are affected by emotional factors and involve a single organ system, usually under AUTONOMIC NERVOUS SYSTEM control. (American Psychiatric Glossary, 1988)Persian Gulf Syndrome: Unexplained symptoms reported by veterans of the Persian Gulf War with Iraq in 1991. The symptoms reported include fatigue, skin rash, muscle and joint pain, headaches, loss of memory, shortness of breath, gastrointestinal and respiratory symptoms, and extreme sensitivity to commonly occurring chemicals. (Nature 1994 May 5;369(6475):8)Toluene: A widely used industrial solvent.Environment, Controlled: A state in which the environs of hospitals, laboratories, domestic and animal housing, work places, spacecraft, and other surroundings are under technological control with regard to air conditioning, heating, lighting, humidity, ventilation, and other ambient features. The concept includes control of atmospheric composition. (From Jane's Aerospace Dictionary, 3d ed)