Reference: 1999 Consensus on Multiple Chemical Sensitivity. Archives of Environmental Health, May/June 1999, Vol. 54, No. 3, based on: J. R. Nethercott, L. L. Davidoff, B. Curbow. “Multiple Chemical Sensitivities Syndrome: Toward a Working Case Definition.” Arch Environ Health, 1993; 48:19–26.

These diagnostic criteria were then validated by University of Toronto researchers, who also determined additional symptoms common in people with MCS.

• Having a stronger sense of smell than others.
• Difficulty concentrating.
• Feeling dull or groggy.
• Feeling spacey.

Reference: McKeown-Eyssen, G. E., C. J. Baines, L. M. Marshall, et al. “Multiple Chemical Sensitivity:
Discriminant Validity of Case Definitions.” Arch Environ Health, 2001; 56(5):406–12

Diagnostic Checklists –Ontario College of Family Physicians website www.ocfp.ca (go to Environmental Health Committee and scroll down)