Getting Started with Multiple Chemical Sensitivity (MCS)
There is no cure for MCS, but there is a clear path forward. Reducing exposure to chemical triggers is the most effective approach supported by the medical literature. Start here.
What Is Multiple Chemical Sensitivity (MCS)?
Multiple Chemical Sensitivity (MCS) is a chronic condition in which individuals experience symptoms triggered by exposure to volatile organic compounds (VOCs) and other chemicals found in fragranced and conventional products, including personal care products, cleaning and laundry products, air fresheners, and chemicals emitted from building materials and furnishings.
MCS is a recognized disability nationally and internationally. Due to sensitization from chemical exposures, it can affect multiple body systems and make it difficult to access spaces essential for everyday living, such as workplaces, healthcare settings, schools, and public places.
Continued exposure leads to worsening symptoms and broader sensitization. Reducing exposure is not optional for good health management. It is the foundation of it.
Learn More About MCS →
Illustrative frequency based on clinical literature. Individual experience varies.
Your First Steps After an MCS Diagnosis
When you first recognize that chemical exposures are affecting your health, the path forward can feel overwhelming. These three priorities give you a clear starting point.
Identify Your Triggers
Track where and when symptoms occur. Common triggers include fragranced products, cleaning agents, laundry products, personal care items, air fresheners, building materials, and new furnishings. A simple exposure log helps identify patterns.
Reduce Exposure at the Source
The most effective management strategy is removing triggering products from your environment, starting with those you use most often. Fragrance-free, lowest volatile organic compound (VOC) emission, and least-toxic alternatives exist for virtually every product category.
Establish Stable Routines
Consistency reduces cumulative exposure. Establish routines that protect your energy, minimize exposure in high-use spaces, and allow your body to stabilize. Small, sustained changes deliver more benefit than large but inconsistent efforts.
The Core Principle: Source Control
Ventilation after chemicals are released is far less effective than preventing exposure at the source. Choosing fragrance-free and lowest-emission products is always preferable to attempting to air out exposures after the fact. This principle applies at home, in healthcare settings, and in workplaces. See safer product guidance →
Why Indoor Air Quality Matters
People spend approximately 90% of their time indoors. The US Environmental Protection Agency (EPA) reports that indoor air can be 10 times or more polluted than outdoor air, due to the accumulation of chemicals from everyday products.
For people living with MCS, indoor air quality is a health and safety issue, not a comfort issue. The products used in a space directly determine the air quality in that space and the chemicals that everyone in it breathes.
Top Sources of Indoor Chemical Exposure
- Fragranced personal care products (shampoo, deodorant, lotions, perfumes)
- Laundry detergents and fabric softeners containing fragrance
- Cleaning and disinfecting sprays
- Air fresheners, scented candles, and wax melts
- New furniture, carpeting, or flooring off-gassing VOCs
- Renovation and construction materials
- Pesticides and pest-control products
- Mould and biological contaminants in damp spaces
Transition Rule: Go at Your Own Pace
Make changes room by room. Start with the highest-impact spaces where you spend the most time. After removing the most problematic products from one area, the next room becomes easier. Do not pour toxic cleaners down the drain or throw them in household garbage; contact your municipality for safe disposal.
Relative exposure frequency for people with MCS. Individual experience varies significantly.
Six Things You Can Do Right Now to Improve Indoor Air Quality
Eliminate Scented Products
Replace all fragranced cleaning, laundry, and personal care products with fragrance-free alternatives. Fragrance is a broad chemical mixture and one of the most common MCS triggers.
Ventilate Regularly
Open windows when weather and outdoor air quality allow. Use exhaust fans in kitchens and bathrooms. Ventilation supports but does not replace source control.
Add Air-Purifying Plants
Spider plants, dracaenas, common ivy, aloe vera, and rubber plants are natural air purifiers. Wipe leaves periodically and monitor soil for mould growth.
Install a HEPA Air Purifier
Air purifiers with HEPA filtration remove fine particles and chemical pollutants. Clean or replace filters regularly to maintain effectiveness.
Address Mould
Mould is a significant contributor to indoor air pollution and a serious MCS trigger. Half of all buildings have some water damage. Inspect under sinks, behind cabinets, and around windows. Never tolerate a known mould source.
Read Labels Every Time
Labels such as "natural," "eco-friendly," "green," or "botanical" have no legal definition. Always check ingredient lists and avoid fragrance, parfum, and the chemicals listed on our safer products page.
What to Do When You First Develop MCS
MCS can begin following a single large chemical exposure, or develop gradually through long-term, low-level exposures at home or in the workplace. Early action reduces the risk of worsening sensitization.
- Identify and remove the most significant exposure sources from your daily environment
- Inform your healthcare provider and request that MCS be clearly documented in your file
- Begin replacing high-exposure products at home, starting with laundry, cleaning, and personal care
- Request workplace accommodation if occupational exposures are contributing to symptoms
- Contact ASEQ-EHAQ for resources, support, and guidance
- Do not attempt to push through exposures. Each exposure can deepen sensitization
- Track which exposures cause symptoms and what improves your condition
- Be patient. Improvement takes time and consistent exposure reduction
Download: What to Do When You Develop MCS (ASEQ-EHAQ)
Download PDFExplore: ASEQ-EHAQ Eco Living Guide - healthy product alternatives
Visit Guide →Do Not Be Misled by Label Claims
Terms like "natural," "green," "eco-friendly," and "botanical" have no legal definitions in Canada. They are marketing terms, not safety guarantees. Here is how to evaluate a product.
Always Read the Ingredient List
The first ingredient is present in the greatest amount. The last, the least. Not all ingredients are required to be disclosed. Any product listing "fragrance," "parfum," or "perfume" should be avoided.
Choose Shorter Ingredient Lists
Fewer ingredients means fewer potential exposures. Seek products with simple, recognizable ingredients. When in doubt, less is safer.
Buy Fragrance-Free, Not "Lightly Scented"
Unscented products may still contain masking fragrances. Look specifically for "fragrance-free" on the label. If fragrance or parfum appears anywhere in the ingredient list, the product contains fragrance chemicals.
Use Fewer Products Overall
Every product added to your daily routine is a potential exposure. Reducing the total number of products used is a meaningful exposure-reduction strategy in itself.
Check Independent Resources
EWG's Skin Deep database (ewg.org/skindeep) and Less Toxic Guide (lesstoxicguide.ca) provide independent safety ratings for specific products and ingredients.
Avoid Endocrine Disruptors
Parabens (look for methyl-, ethyl-, butyl-, propyl- prefixes), phthalates, bisphenol A, and triclosan are among the most common endocrine-disrupting chemicals found in household and personal care products.
Where to Go Next
Getting started is the first step. Each section below goes deeper into a specific area of managing MCS day to day.
Need Support? Contact ASEQ-EHAQ
ASEQ-EHAQ supports people with MCS and their families through resources, information, education, advocacy, and awareness. Contact us directly if you need guidance or support.