This article aims to summarize current knowledge relating to the aging processes of the brain. Several approaches have been carried out to study the changes in the aging brain, from gross-anatomical studies to the molecular events within cells. Out of the prominent alterations which have been detected are cortical atrophy, neuronal loss, accumulation of the aging pigment-lipofuscin, lower brain metabolism, lower activities of neurotransmitter systems, changes in hormonal regulations, and lower or higher cellular responses to neurohumoral agents or drugs. Aging of the brain may be a new state of functioning as a result of shifts in the balances between cell groups or areas of the brain. These changes may be a critical step in producing sequences of responses to the whole body; the information from other organs, however, also influences brain functions. Several lines of information about the pathology of the elderly brain and the drug treatment of these disorders are also discussed. Progresses in research on Alzheimer's dementia have been reviewed in several articles in the past year; the effective pharmacotherapy, however, awaits further investigation. The uses of drugs in other organic brain syndromes need a very careful study and evaluation. Drugs currently used such as vasodilators and derivatives of ergot alkaloids may have only limited advantage in a particular group of patients.