Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (752 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
An acquired disorder characterized by recurrent symptoms, referable to multiple organ systems, occurring in response to demonstrable exposure to many chemically unrelated compounds at doses below those established in the general population to cause harmful effects. (Cullen MR. The worker with multiple chemical sensitivities: an overview. Occup Med 1987;2(4):655-61)
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Multiple Chemical Sensitivities; Multiple Chemical Sensitivity Syndrome; Sensitivities, Multiple Chemical; Chemical Sensitivities, Multiple; Chemical Sensitivity, Multiple; Idiopathic Environmental Intolerance; Environmental Intolerance, Idiopathic; Environmental Intolerances, Idiopathic.
Where it fits in the MeSH classification
- Broader topics
- Environmental Illness
- See also
- Persian Gulf Syndrome
Research landscape
PubMed indexes 842 records tagged with the MeSH heading “Multiple Chemical Sensitivity” (counts retrieved 2026-10-29). 92 of them (10.9%) were published from 2020 onward, and the busiest period so far is 2000-2009 with 305 records.
Reviews account for 229 records (27.2%) and meta-analyses for 4. Randomized controlled trials number 29 (3.4%) as a share of all records on the topic.
Show the data
| Period | Records |
|---|---|
| through 1999 | 258 |
| 2000-2009 | 305 |
| 2010-2019 | 187 |
| 2020 onward | 92 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 229 | 27.2% |
| Meta-analyses | 4 | 0.5% |
| Randomized controlled trials | 29 | 3.4% |
Method: PubMed query "Multiple Chemical Sensitivity"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-29.
Reading the evidence in immunology
Immune responses are studied in model organisms, in cells from donors and in patients, and the same pathway can behave differently across these settings. Mouse immune systems differ from human ones in important ways, and blood measurements may not reflect what happens in tissues. Clinical conclusions about immune-mediated disease or immunotherapy come mainly from controlled trials and long-term cohorts. Check the species and tissue studied, whether markers were linked to outcomes patients notice, and the follow-up time.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Study of self-reported hypersensitivity to electromagnetic fields in California | 2002 | Research article Design not recorded in structured metadata | 83 | cc by PMID 12194896 · DOI · PMC1241215 |
| A review of a two-phase population study of multiple chemical sensitivities | 2003 | Review article Design not recorded in structured metadata | 71 | cc by PMID 12948889 · DOI · PMC1241652 |
| Perceived treatment efficacy for conventional and alternative therapies reported by persons with multiple chemical sensitivity | 2003 | Research article Design not recorded in structured metadata | 66 | cc by PMID 12948890 · DOI · PMC1241653 |
| Prevalence of Multiple Chemical Sensitivity in Canada Between 2000 and 2020 | 2026 | Research article Design not recorded in structured metadata | 3 | cc by PMID 41752318 · DOI · PMC12940565 |
Study of self-reported hypersensitivity to electromagnetic fields in California [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Cases of alleged hypersensitivity to electromagnetic fields (EMFs) have been reported for more than 20 years, and some authors have suggested some connection with the "multiple chemical sensitivity" illness.
- Closing excerpt
- However, risk perception was not sufficient to explain the characteristics of people reporting this disorder.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (201 words)
Cases of alleged hypersensitivity to electromagnetic fields (EMFs) have been reported for more than 20 years, and some authors have suggested some connection with the "multiple chemical sensitivity" illness. We report the results of a telephone survey among a sample of 2,072 Californians. Being "allergic or very sensitive" to being near electrical devices was reported by 68 subjects, resulting in an adjusted prevalence of 3.2% (95% confidence interval = 2.8, 3.7). Twenty-seven subjects (1.3%) reported sensitivity to electrical devices but no sensitivity to chemicals. Characteristics of the people reporting hypersensitivity to EMFs were generally different from those of people reporting being allergic to everyday chemicals. Alleging environmental illness or multiple chemical sensitivity diagnosed by a doctor was the strongest predictor of reporting being hypersensitive to EMFs in this population. Other predictive factors apart from self-reporting chemical sensitivity were race/ethnicity other than White, Black, or Hispanic; having low income; and being unable to work. The perception of risk of exposure to EMFs through the use of hair dryers (vs. exposure to power and distribution lines) was the factor the most associated with self-reporting about hypersensitivity to EMFs. However, risk perception was not sufficient to explain the characteristics of people reporting this disorder.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 12194896 · DOI · PMC1241215
A review of a two-phase population study of multiple chemical sensitivities [2]
Abstract reading summary — source excerpts
- Opening excerpt
- In this review we summarize the findings of a two-phase study of the prevalence, symptomatology, and etiology of multiple chemical sensitivities (MCS).
- Closing excerpt
- This suggests that MCS has a physiologic and not a psychologic etiology.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (191 words)
In this review we summarize the findings of a two-phase study of the prevalence, symptomatology, and etiology of multiple chemical sensitivities (MCS). We also explore possible triggers, the potential linkage between MCS and other disorders, and the lifestyle alterations produced by MCS. The first phase of the study consisted of a random sampling of 1,582 individuals from the Atlanta, Georgia, metropolitan area to determine the reported prevalence of a hypersensitivity to common chemicals. In this phase, 12.6% of the sample reported a hypersensitivity. Further questioning of individuals with a hypersensitivity indicated that 13.5% (1.8% of the entire sample) reported losing their jobs because of their hypersensitivity. The second phase was a follow-up questioning of the respondents who initially reported hypersensitivity. In this phase, we found that individuals with hypersensitivity experience a variety of symptoms and triggers. A significant percentage (27.5%) reported that their hypersensitivity was initiated by an exposure to pesticides, whereas an equal percentage (27.5%) attributed it to solvents. Only 1.4% had a history of prior emotional problems, but 37.7% developed these problems after the physical symptoms emerged. This suggests that MCS has a physiologic and not a psychologic etiology.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 12948889 · DOI · PMC1241652
Perceived treatment efficacy for conventional and alternative therapies reported by persons with multiple chemical sensitivity [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Multiple chemical sensitivity (MCS) is a condition in which persons experience negative health effects in multiple organ systems from exposure to low levels of common chemicals.
- Closing excerpt
- We discuss this drain on personal resources and describe respondents' attitudes toward the possibility of healing from MCS.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (177 words)
Multiple chemical sensitivity (MCS) is a condition in which persons experience negative health effects in multiple organ systems from exposure to low levels of common chemicals. Although symptoms experienced from particular chemicals vary across persons, they are generally stable within persons. The sensitivities often spread over time, first to related chemicals and then to other classes of chemicals. This study examined self-reported perceived treatment efficacy of 101 treatments used by 917 persons with self-reported MCS. Treatments examined included environmental medicine techniques, holistic therapies, individual nutritional supplements, detoxification techniques, body therapies, Eastern-origin techniques, newer therapies, prescription items, and others. The three most highly rated treatments were creating a chemical-free living space, chemical avoidance, and prayer. Both creating a chemical-free living space and chemical avoidance were rated by 95% of respondents as helpful. Results for most therapies were mixed. Participants had consulted a mean of 12 health care providers and spent over one-third of their annual income on health care costs. We discuss this drain on personal resources and describe respondents' attitudes toward the possibility of healing from MCS.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 12948890 · DOI · PMC1241653
Prevalence of Multiple Chemical Sensitivity in Canada Between 2000 and 2020 [4]
Abstract reading summary — source excerpts
- Opening excerpt
- Multiple chemical sensitivity (MCS) describes an acquired condition characterized by recurrent, non-specific symptoms attributed to previously tolerated chemical exposure.
- Closing excerpt
- The observed prevalence aligns with international estimates, underscoring MCS as an emerging public health concern in Canada.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (183 words)
Multiple chemical sensitivity (MCS) describes an acquired condition characterized by recurrent, non-specific symptoms attributed to previously tolerated chemical exposure. Although Canada collects national data on MCS through population health surveys, the condition remains poorly understood and under-studied. This study analyzes data from the Canadian Community Health Survey (2000-2020) to examine trends in MCS prevalence across demographic characteristics, including province of residence, sex, and age. Descriptive analyses were used to assess temporal changes and differences between regions and population subgroups. Between 2000 and 2020, the proportion of Canadians reporting an MCS diagnosis increased from 1.9% to 3.5%. Prevalence varied geographically, with higher rates consistently observed in the Atlantic provinces compared with the Prairie provinces. MCS prevalence increased with age in both sexes; however, rates were higher among young males than females, with this pattern reversing in mid-life as prevalence became higher among females. These findings provide a national overview of MCS prevalence over two decades and offer relevant information for public health authorities, healthcare professionals, and researchers. The observed prevalence aligns with international estimates, underscoring MCS as an emerging public health concern in Canada.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41752318 · DOI · PMC12940565
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Breathtaking TRP channels: TRPA1 and TRPV1 in airway chemosensation and reflex control [5]
- Research article Multiple chemical sensitivity syndrome (MCS)--suggestions for an extension of the U.S. MCS-case definition [6]
- Research article Multiple chemical sensitivities: A systematic review of provocation studies [7]
- Research article A review of multiple chemical sensitivity [8]
- Research article Neurogenic switching: a hypothesis for a mechanism for shifting the site of inflammation in allergy and chemical sensitivity [9]
- Research article Do people with idiopathic environmental intolerance attributed to electromagnetic fields display physiological effects when exposed to electromagnetic fields? A systematic review of provocation studies [10]
References
- Levallois P, Neutra R, Lee G, Hristova L. Study of self-reported hypersensitivity to electromagnetic fields in California. . 2002. PMID 12194896 · DOI · PMC1241215
- Caress SM, Steinemann AC. A review of a two-phase population study of multiple chemical sensitivities. . 2003. PMID 12948889 · DOI · PMC1241652
- Gibson PR, Elms AN, Ruding LA. Perceived treatment efficacy for conventional and alternative therapies reported by persons with multiple chemical sensitivity. . 2003. PMID 12948890 · DOI · PMC1241653
- Robins S, Molot J, Peris R. Prevalence of Multiple Chemical Sensitivity in Canada Between 2000 and 2020. . 2026. PMID 41752318 · DOI · PMC12940565
- Bessac BF, Jordt SE. Breathtaking TRP channels: TRPA1 and TRPV1 in airway chemosensation and reflex control. Physiology (Bethesda). 2008. PMID 19074743 · DOI · PMC2735846
- Lacour M, Zunder T, Schmidtke K, Vaith P, Scheidt C. Multiple chemical sensitivity syndrome (MCS)--suggestions for an extension of the U.S. MCS-case definition. Int J Hyg Environ Health. 2005. PMID 15971853 · DOI
- Das-Munshi J, Rubin GJ, Wessely S. Multiple chemical sensitivities: A systematic review of provocation studies. J Allergy Clin Immunol. 2006. PMID 17137865 · DOI
- Graveling RA, Pilkington A, George JP, Butler MP, Tannahill SN. A review of multiple chemical sensitivity. Occup Environ Med. 1999. PMID 10448311 · DOI · PMC1757696
- Meggs WJ. Neurogenic switching: a hypothesis for a mechanism for shifting the site of inflammation in allergy and chemical sensitivity. Environ Health Perspect. 1995. PMID 7628426 · DOI · PMC1519059
- Rubin GJ, Hillert L, Nieto-Hernandez R, van Rongen E, Oftedal G. Do people with idiopathic environmental intolerance attributed to electromagnetic fields display physiological effects when exposed to electromagnetic fields? A systematic review of provocation studies. Bioelectromagnetics. 2011. PMID 21769898 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-29.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.