The objective of this review is to assess the role of clinical toxicology as it is practiced today and its possible future development. This includes the legal and ethical aspects of the subject and their application to man. The following issues are considered: extrapolation from animal to man; the logical sequence of the implementation of the stages that constitute good clinical practice; examples of the main invasive and noninvasive techniques employed in the clinical studies; the monitoring of the health of the employee in his working environment; chemically induced chronic disease states; and a retrospective consideration of specific examples of chemical hazards.