Prevalence & Recognition
The number of people diagnosed with Multiple Chemical Sensitivity (MCS) in Quebec has shown a consistent increase over time, from 173,500 in 2015 to 230,500 in 2016 and 251,000 in 2020. Data sourced from the Canadian Community Health Survey (CCHS), 2015, 2016, and 2020.
The number of people diagnosed with Multiple Chemical Sensitivity (MCS) in Canada — 940,500 in 2015, 1,008,400 in 2016, and 1,130,800 in 2020, showing a consistent increase over time. Data sourced from the Canadian Community Health Survey (CCHS), 2015, 2016, and 2020.
The chart highlights the large gap between individuals who self-report chemical sensitivity and those who receive a formal diagnosis. Globally, an estimated 9–16% of people report some level of sensitivity, while only 0.5–4% are formally diagnosed with Multiple Chemical Sensitivity (MCS). This difference suggests that many affected individuals remain undiagnosed or under-recognized within the healthcare system. Data sourced from the Canadian Community Health Survey (CCHS) 2020
Many people around the world report being sensitive to chemicals, with an estimated 9–16% of the global population experiencing some level of reaction to them. However, only a small number—around 0.5–4%—receive a formal diagnosis of Multiple Chemical Sensitivity (MCS).
In Canada, about 3.52% of the population has been diagnosed with MCS. In Québec, the percentage of diagnosed cases is 3.44%. The number of diagnosed cases has risen sharply, increasing by 200–300% over the past decade. In 2020, this meant that roughly 1.13 million Canadians were living with a confirmed diagnosis of MCS.