What is MCS?

The 1999 Consensus Criteria for Multiple Chemical Sensitivity.

Taken from the pdf available at mcsrr.org.

  1. The symptoms are reproducible with repeated (chemical) exposures.
  2. The condition is chronic.
  3. Low levels of exposure (lower than previously or commonly tolerated) result in manifestation of syndrome.
  4. The symptoms improve or resolve when the incitants are removed.
  5. Responses occur to multiple chemically unrelated substances.
  6. Symptoms involve multiple organ systems.

The following is taken from the brochure, 

Multiple Chemical Sensitivities: A look at a growing problem.



Multiple Chemical Sensitivities (MCS) is a medical condition characterized by debilitating chemical sensitivities. People who are chemically sensitive are made sick by exposures to chemicals found in many common products such as pesticides, perfumes, tobacco smoke, new carpets, air “fresheners,” new paint and building materials, and many cleaning and laundry products. Most of these chemicals will make everyone sick at high levels, but for chemically sensitive people exposures to even small amounts of these substances can cause symptoms. Some chemically sensitive people are only mildly affected while others have the more severe form of the illness called MCS.



MCS is a serious and growing public health problem that affects people of all ages, races, and economic backgrounds. A 1997 survey conducted by the New Mexico Department of Health found that 16% of the state’s respondents reported being unusually sensitive to everyday chemicals, like household cleaning products, paints, perfumes and insect sprays, and 2% reported they had been diagnosed with MCS.



Symptoms experienced by people with MCS range from mild to life-threatening and include headache, trouble concentrating, nausea, diarrhea, fatigue, muscle and joint pain, dizziness, difficulty breathing, irregular heart beat, and seizures. MCS symptoms in children include red cheeks and ears, dark circles under the eyes, hyperactivity, and behavior or learning problems. After an exposure, symptoms may occur immediately or be delayed for up to a few days. Reactions may last from a few seconds to weeks or months. People with MCS often react to a variety of foods, drugs, molds, and pollen as well as chemicals.