Multiple chemical sensitivities (MCS) is a disabling, invisible and stigmatised chronic illness and a contested medical diagnosis. This paper describes social issues of MCS sufferers who look well but who can become rapidly disabled in certain environments. Such issues include others’ unrealistic expectations, insensitive remarks, treatment or even harassment based on disbelief or bias, and economic/occupational liabilities. Legal cases are just beginning to be won with regard to accommodation under the ADA, but they are rare. The authors’ perspectives are based on personal experience, organisational/policy activism, and ethnographic research on MCS.