Clinical Definition --MCS

A large group of names have been applied to an Illness many of us call Multiple Chemical Sensitivities. A major hindrance in achieving scientific respectability for MCS has been the difficulty in agreeing upon a definition for this condition. 

The 2 following definitions are widely used by many Doctors that have training and understanding of MCS.


One definition on the comes from Dr. Mark Cullen, Yale School of Medicine and quoted by most Occupational and Environmental Doctors. This case definition, is intentionally narrow.  Cullen excludes persons who react to substances no one else is aware of on the basis that such individuals may be delusional and excludes persons who have bronchospasm, vasospasm, seizures, or "any other reversible lesion" that can be identified and specifically treated.

Multiple Chemical Sensitivities (MCS) is 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 far below those established in the general population to cause harmful effects.  No single widely accepted test of physiologic function can be shown to correlate with symptoms


Clinical ecologists, however, would argue that persons with bronchospasm, vasospasm, seizures, and other illness excluded by Cullen may well have the chemical sensitivity problem. 

Each issue of the clinical ecologists' journal, Clinical Ecology, contains the following message

Ecologic Illness is a chronic multi-system disorder, usually polysymptomatic, caused by adverse reactions to environmental incitants, modified by individual susceptibility and specific adaptation.  The incitants are present in air, water, food, drugs and our habitat.

(Chemical Exposures -- Low levels, High stakes -- Ashford Miller) 1991

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