[Questionable procedures in environmental medicine using an example of "multiple chemical sensitivity"]

"Multiple Chemical Sensitivity" (MCS) has to be regarded as a merely subjective concept without etiological and pathological background or objective criteria for diagnosis. Most of the "MCS" patients suffer from various psychiatric disorders; in a small minority somatic diseases can be found. The data recently won in the German multicenter study on MCS underline this point of view. The informal German "MCS network" consisting of patients' self-help groups, "therapists" with or without medical background and law firms specialised in compensation claims nevertheless strictly denies any psychogenic model. They do, however, propose a whole range of diagnostic and therapeutic procedures based on different theoretical concepts. Some of the procedures are derived from scientifically based medicine, others have an unconventional and esoteric background. Most of them are logically incompatible; however, they are applied in a polypragmatic manner. None of these so-called diagnostic or therapeutic procedures or health technologies can be regarded as evidence-based. Some of them, however, are extremely expensive and/or pose significant risks for patients' health. In any case, wrong subjective disease concepts are perpetuated iatrogenically. Additionally, those procedures make effective help for the real underlying medical and/or psychiatric conditions impossible.