Suspicions of the impact of oestrogen beyond its traditional role in sex maturation were confirmed with the discovery of oestrogen receptors in a great variety of tissues other than just in sex organs. Recently, research findings have indicated the central nervous system as one of the prime target organs--not only does oestrogen modulate the production and actions of serotonin, acetylcholine, dopamine and norepinephrine, but it also encourages the growth of new synapses and enhances neuronal survival. Whether the many effects of oestrogen operate through classical oestrogen receptors or alternative channels remains under intense investigation. During this three-day symposium, researchers and clinicians discussed a wide-range of oestrogen-related subjects from novel mechanisms of action to the influence of oestrogen on cognition and behaviour, and results from clinical studies that suggest oestrogen therapy after menopause may protect from Alzheimer's disease.