Multiple Chemical Sensitivity (MCS)

„Multiple Chemical Sensitivity“ (MCS) is characterised by general symptoms such as fatigue, exhaustion, respiratory problems, symptoms of the gastrointestinal tract and further malfunctions of various organ systems.

Persons affected by MCS attribute these symptoms to exposure to different kinds of chemicals and environmental noxae, whereby even very low concentrations, which do not cause health problems in other people, lead to ailments. Hitherto, neither does a universally accepted definition of which symptoms pertain to MCS nor do verified findings on the environmental causes of the symptoms exist.

According to the consensus criteria (Bartha et al., 1999) MCS is characterised by

  1. symptoms that are reproducible if chemical exposition is repeated,
  2. a chronic state,
  3. symptoms that are triggered by low dosages, which were tolerated by the person before or which in general are tolerated by other people,
  4. symptoms that decrease or stop when chemical triggers are avoided,
  5. symptoms that are caused by various, non-related substances,
  6. involvement of multiple organs or organ systems of a person.

Several mechanisms regarding the development of MCS have been proposed that can be broadly assigned to disorders in immunologic or allergic processes, changes in the functioning of the nervous system, alterations in biochemical processes or changes in psychological respectively neurobehavioral functions (Winder, 2002). To date it has not been clarified whether, and if so, which mechanisms contribute to the development of MCS.

On behalf of the German Environment Agency (Umweltbundesamt; UBA) the Robert-Koch-Institute coordinated several studies about the MCS syndrome. In summary, no scientifically justifiable mechanisms for the development of MCS were found in the three conducted studies (Eis et al., 2008). It remains uncertain whether MCS is an independent disease. Noticeably, psychosomatic strains often co-occur with MCS-problems. However it is unclear whether, in case of such co-occurrence, MCS symptoms are the cause or the result of psychosomatic strains.

The personal consequences of MCS are – much like the symptoms – diverse. Persons affected report amongst other things limitations in quality of life as well as in performance capacity and often feel unable to practice their job. Taking care of mundane tasks as well as social interaction with friends and family are oftentimes experienced as problematic and conflict-ridden. The level of suffering of MCS patients can be very high and in extreme cases may lead to social isolation.

MCS is a broad symptom complex, which often compromises the lives of affected persons. Depending on the personal situation, concerned persons may obtain information and assistance in environmental-medical outpatient clinics and counselling centres, in public health departments as well as from general practitioners and experts for environmental medicine. Differential diagnostics of other diseases that may lead to similar symptoms (i.e. allergies, food intolerances, mental disorders) are important to treat possible accompanying illnesses. Therefore, potential allergic reactions of the organism to certain substances should be checked for medically. Foremost, the support of the patient in his or her everyday life is important. Cognitive behavioural interventions can help with coping and can provide some relief of the strain. The UBA therefore recommends interdisciplinary evaluation of the symptoms to ensure optimal care.


Bartha, L., Baumzweiger, W., Buscher, D. S., Callender, T., Dahl, K. A., Davidoff, A., ... & Flayhan, D. P. (1999). Multiple chemical sensitivity: a 1999 consensus. Archives of Environmental Health, 54(3), 147-149.

Eis, D., Helm, D., Mühlinghaus, T., Birkner, N., Dietel, A., Eikmann, T., ... & Gil, F. P. (2008). The German multicentre study on multiple chemical sensitivity (MCS). International journal of hygiene and environmental health, 211(5), 658-681.
Winder, C. (2002). Mechanisms of multiple chemical sensitivity. Toxicology letters, 128(1), 85-97.

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 Multiple Chemical Sensitivity  fatigue stress  syndrome  chemicals