The mechanism through which nootropics of the piracetam type (i.e., piracetam itself and its analogues oxiracetam, pramiracetam, and aniracetam) improve memory is still uncertain. Its elucidation will, however, not only mark an advance in the treatment of cognitive disorders, but also shed light on the basic processes of memory storage. Although the great majority of the findings available so far seem to suggest cholinergic mechanisms, divergent results are obtained whenever parallel experiments are performed with two or more of these compounds. More recent observations indicate that interactions with steroids take place. All four compounds are inactive in adrenalectomized laboratory animals; chemical blockade of the adrenal cortex with aminoglutethimide and pretreatment which epoxymexrenon, a potent mineralocorticoid antagonist, eradicated the memory-enhancing effect of all four substances.