Piracetam, the prototype of nootropic drugs, is claimed to have therapeutic value in some patients suffering from cognitive deficits, especially when hypoxia may be a factor in the deficits. The drug lacks sedative or stimulatory effects and apparently does not influence behavior in normal people. The site of action and the mechanism by which piracetam exerts its beneficial effects are not well established. This review has summarized experimental and clinical data on its absorption, distribution, and excretion, and described the biochemical data available that bear on its mechanism of action.