The pharmacology of memory is fraught with problems. For one thing, the lack of consensus on the definition of memory and the absence of reference compound create clinical validation problems for new drugs. Then, it is difficult to predict clinical effectiveness on the basis of animal experiments and data obtained from healthy subjects, and this is due to the lack of analogy between animal models and clinical situations. Finally, to this must be added the complexity and variety of the possible modes of action of the agents under study. Thus, the pharmacology of cognition activators is closely dependent upon both fundamental research and clinical research.