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Chemical Intolerance And Chronic Illness

Posted by Manuela Boyle on 6 August 2022
Chemical Intolerance And Chronic Illness

Chemical intolerance is often the common denominator for patients with chronic and complex illnesses that frustrate clear diagnoses and are unresponsive to care.

How common?Research indicates that one in five patients are seeking care because of chemical intolerance. Learn how to screen patients for chemical intolerance, the genetics and biochemistry involved, and therapeutic protocols for resolving this surprisingly common yet typically unrecognised condition.

Four senses (sight, smell, taste, and touch) out of our five, encounter common chemicals every day. They’re found in pesticides, petrol, perfumes, vehicle exhaust, household cleaning products, personal care products, cigarette smoke, and others. Do you feel the following symptoms when you’re around these common chemicals?
If you experience the symptoms mentioned above in the presence of common chemicals, you might have Multiple Chemical Sensitivity (MCS) , also known as Idiopathic Environmental Intolerance. Simply put, it’s a collection of signs and symptoms you may experience upon repeated exposure to small amounts of chemicals you encounter every day over a prolonged period. It’s unfortunate that at the writing of this article, there’s still much debate whether Multiple Chemical Sensitivity or MCS for short, is a real disease entity or just a psychological one (it’s all in your head).


Chemicals in everyday products are the known triggers of MCS. But what is its exact cause? Nobody knows the exact cause or causes. A person who notices that he is sensitive to a chemical will quickly experience the onset of symptoms over a relatively short period. The chronic exposure to low levels of everyday chemicals will eventually lead to a point where your body can’t tolerate them any longer. You then become sensitised (your body becomes irritable) leading to the development of MCS symptoms.

The limbic system in your brain becomes hyperactive. Your limbic system is responsible for your emotions, mood, and communication in your autonomic nervous system. It’s no surprise that many symptoms of MCS can involve mood and behaviour. Researchers have observed that electrical activity in patients with MCS is increased, leading to heightened sensitivity to everyday chemicals compared to those who don’t have MCS.

People with MCS were also found to have defective detoxification of xenobiotic chemicals (foreign chemical substances) and low levels of glutathione (a powerful antioxidant) which is important for part of your livers detoxing actions. You know what that means, you get more circulating levels of toxic chemicals in your body.

Chronic, low-level exposure to everyday chemicals may impair parts of your body’s immune system.

MCS may increase in severity over time. Researchers describe the stages of MCS as follows: 

Stage 0 — Tolerance: You may be exposed to chemical triggers, but your body is able to adapt to it if the exposure is minimal. 
Stage 1 — Sensitisation: Low concentrations over short or long periods of time start to activate a range of vague symptoms. They may be overlooked as something else and are difficult to correlate with the exposure. 
Stage 2 — Inflammation:  Your organ systems begin to have chronic inflammation. Exposures to triggers may last for several days, even weeks.
Stage 3 — Deterioration: Your central nervous system becomes impaired. Chronic inflammation increases, which can start to damage organs. That may generate more severe forms of chronic diseases, such as heart attacks, and autoimmune issues. 

How Do You Identify Multiple Chemical Sensitivity?
The responses from MCS can vary from person to person. The same chemical can give two people with MCS completely different reactions. It also depends on the level of toxin exposure. Higher amounts may create a much more intense response. 

Here’s some of the most common MCS symptoms, as well as other issues that can accompany MCS.   

When you first start to experience MCS, you might brush off the symptoms or attribute them to something else. But these responses can escalate over time. You may develop severe reactions that happen immediately on exposure. 

Reactions or symptoms could include: 

  • Rashes
  • Joint pain 
  • Nausea 
  • Fatigue 
  • Headaches 
  • Gut issues  
  • Blood pressure changes 
  • Asthma attacks 
  • Brain fog 
  • Dermatitis 
  • Hormone disorders 
  • Fainting 
  • Poor circulation 
  • Bleeding in your extremities or on your skin 
  • Food and environmental allergies

Associated Issues
Researchers have also noticed that people with MCS have higher rates of other disorders and diseases. Rates of chronic fatigue and fibromyalgia are greater among those with MCS. Issues with the respiratory system — such as asthma, bronchitis, pneumonia, and sinusitis — are also prevalent. 

MCS might also affect your mental health. Studies suggest that MCS may be associated with panic disorder, depression, schizophrenia, and attention deficit hyperactivity disorder (ADHD). 

Researchers believe that the inflammation MCS generates in your body increases the likelihood of developing other issues. As an additional factor, MCS also damages your central nervous system. 

Do You Have Multiple Chemical Sensitivity?
With the complexity of symptoms and how much they vary between people, identifying MCS can be difficult. There isn’t a standard blood test, for example, that can diagnosis MCS. 

But you can take a questionnaire called the Quick Environmental Exposure and Sensitivity Inventory (QEESI). The QEESI is a scientifically-validated test developed through extensive research and clinical assessment. (ASK Us)

This simple test helps you assess your symptoms. You can take your results to your healthcare practitioner so he or she can better understand your situation.

While your health issues may appear random, they could all stem from sensitivity to chemicals in your environment. 

Identify Your Triggers
Although everyone with MCS differs, several items do seem to cause the most issues. Be keenly aware if any of the following cause issues for you: 

Pesticides or bug sprays
Air fresheners
Household cleaners
Gas or vehicle exhaust
Perfumes or products containing fragrance
Nail polishes and polish removers
Carpet or new furniture 
Specific foods or chlorinated water
Personal care products, like lotions or hairspray

Author:Manuela Boyle
Tags:NewsPrevention & RecoveryCancerAllergies and SensitivitesPollutants


  • The Institute for Functional Medicine
  • Society for Integrative Oncology
  • American Society of Clinical Oncology
  • Australian Traditional-Medicine Society
  • Naturopaths and Herbalists Association of Australia