ABSTRACT
This chapter begins by contrasting environmental illness with well-characterized, chemically induced diseases. It defines some of the concepts of environmental illness (EI) and the parties who advocate environmental illness as a toxicogenic theory, meaning that ill-health effects are caused by environmental exposures to chemicals at levels tolerated by most of the population. The chapter describes the characteristics of patient symptoms, all of which need to be explained. It provides a brief outline of the two opposing theories—toxicogenic and psychogenic—highlighting the issues to be addressed. The effects of chemicals on disease and particularly the functioning of the nervous system are firmly rooted in antiquity and are universally accepted tenets of modern medical practice. The International Programme on Chemical Safety panel recommended that the use of the label "multiple chemical sensitivity" be discontinued, despite its familiarity in the literature and colloquial use. The chapter also presents an overview of the key concepts discussed in this book.
