Multiple Chemical Sensitivity

People who experience reactions to low levels of common chemicals are said to have multiple chemical sensitivity (MCS).

Exposure to certain chemicals may cause reactions similar to those experienced with allergies. ...once exposed, low levels of chemicals found in everyday materials, such as soaps, detergents, cosmetics, and newspaper inks, can trigger physical symptoms in people with multiple chemical sensitivities.

John Hopkins Medicine, Multiple Chemical Sensitivity

An estimated one million Australians have a condition known as multiple chemical sensitivities or MCS.

The Feed, SBS, 13 Aug 2018

Multiple Chemical Sensitivity (MCS) presents as a complex array of symptoms in response to low level exposure to chemicals. ME/CFS may cause or worsen sensitivities to and intolerances of very low levels of common chemicals and acknowledged toxins. Reactions can range from mild to severe and lead to PEM (post-exertional malaise) or even long-term relapses.

Commonly occurring chemical triggers include:

  • perfumes and fragrances, including essential oils and synthetic forms, that may occur in products such as shampoo, deodorant, laundry detergent, disposable nappies
  • cosmetics, including unscented hairspray and skin care products
  • cleaning products
  • upholstery, carpeting and building materials, including formaldehyde from manufactured wood
  • paints, adhesives, solvents
  • organophosphates, including pesticides, insecticides and herbicides
  • petrochemicals, including exhaust from vehicles and natural gas appliances
  • ozone from printers, copy machines and ozone air purifiers
  • printing ink
  • smoke
  • chlorinated water
  • other volatile organic compounds (VOCs)

People with ME/CFS often do not tolerate usual doses of medication, including anaesthetics.

The 2019 Italian Consensus on Multiple Chemical Sensitivity (English translation) provides an overview of MCS.


Symptoms are wide ranging and include headache, fatigue, dizziness, nausea, congestion, itching, sneezing, sore throat, chest pain, changes in heart rhythm, breathing problems, muscle pain or joint stiffness, skin rash, gastrointestinal symptoms, confusion, trouble concentrating, memory problems, and mood changes.

The Quick Environmental Exposure and Sensitivity Inventory (QEESI) is a diagnostic tool that is often used to assess a patient for these symptoms.


Strategies for managing MCS include avoiding risky environments, wearing a mask, and improving indoor air quality using air filters, air conditioning systems and open windows. Plants can be effective in reducing VOCs in a room.

Where possible, use low-emitting building materials and products such as VOC-free paint; allow furniture and other goods time to out gas before use; and ask others to reduce their use of fragrance. The US Environmental Protection Agency (EPA) provides guides to indoor air quality, including for homes, schools and offices.

When triggers for MCS cause PEM, careful pacing may be required to aid recovery from the exposure.

Accessibility issues

Many premises are not safely accessible to people with MCS. Those who own, lease, operate and manage premises, including rental properties, should minimise the risk of provoking chemical sensitivity reactions by:

  • selecting safer building, cleaning and maintenance chemicals and materials
  • providing adequate ventilation and ensuring all fresh air intakes are clear of identifiable sources of air pollution, such as exhaust fumes from vehicles and stored chemicals
  • avoiding use of air fresheners
  • minimising use of herbicides and pesticides
  • providing early notification of events such as painting, pesticide/herbicide applications or carpet shampooing by way of signs, letters or e-mail

Publications by Dr Anne Steinemann provide further information about indoor air quality.

The Centers for Disease Control and Prevention (CDC) is the largest healthcare employer in the United States, and has adopted a scent-free policy.

Fragrance is not appropriate for a professional work environment, and the use of some products with fragrance may be detrimental to the health of workers with chemical sensitivities, allergies, asthma, and chronic headaches/migraines.

Centers for Disease Control Office of Health and Safety (2009), Indoor Environment Quality Policy (PDF), United States, p.9

The Canadian Centre for Occupational Health and Safety (CCOHS) provides a guide to developing a Scent-Free Policy for the workplace.


Australian National Register of Environmental Sensitivities (ANRES)
ANRES maintains a register of Australians living with environmental senstivities of all kinds. In 2019 they reported on information from their register.

Allergy and Environmental Sensitivity Support and Research Association Inc (AESSRA)
AESSRA is a support group for people with allergies and sensitivities, including MCS.

Chemical Injury Information Network (CIIN)
The CIIN is a support and advocacy organisation for people with MCS and for those who care for them.

Additional search terms: idiopathic environmental intolerance, environmental sensitivities, toxic-induced loss of tolerance (TILT), aerotoxic syndrome, sick-building syndrome (SBS), building-related illness (BRI), organophosphate poisoning, chemical intolerance.

Last edited: 29 August, 2023