This publication explains the principles of the techniques used in disposition and metabolism studies in animals, in man, and in vitro. It includes methods for studying routes and rates of absorption, distribution, metabolism, and excretion of novel compounds and their metabolites. Relevant surgical, whole-body autoradiographic and pharmacokinetic procedures are discussed, together with techniques for separating and identifying metabolites and metabolic path-ways. Information on when the procedures are appropriate, and examples of what they represent, are presented in order to illustrate the value of such studies.