Galantamine, a novel treatment for Alzheimer's disease (AD), has a dual mechanism of action, combining allosteric modulation of nicotinic acetylcholine receptors with reversible, competitive inhibition of acetylcholinesterase. In the Phase III clinical trial programme, over 3,000 patients with mild-to-moderate AD were enrolled in one of five randomized, controlled, double-blind studies. Using the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) to assess memory and other cognitive functions, galantamine was found to be significantly superior to placebo in all five studies at doses of 16, 24 and 32 mg/day. In all studies, galantamine-treated patients maintained their cognitive function, whereas the placebo-treated patients experienced a significant deterioration in ADAS-cog scores. The 32-mg/day dose was not associated with any additional cognitive benefit. Pooled data from two 6-month studies (n = 1,269), which were of identical design, show that the therapeutic benefits of galantamine are sustained for the duration of treatment. The treatment effect (galantamine-placebo difference on ADAS-cog) for the pooled data was approximately 4 points. Clinical benefit was seen in all levels of disease severity, with a 7-point advantage over placebo on ADAS-cog for patients with moderately severe disease. Galantamine was well tolerated, with most patients completing the 6-month studies. The long-term effects of galantamine have been evaluated in a 12-month study. Patients who completed one of the pivotal 6-month studies (n = 353) were entered into a 6-month open-label extension. Cognitive and daily function were maintained throughout the 12 months in patients who received galantamine 24 mg/day. This sustained level of benefit may reflect galantamine's dual effect on the cholinergic system. Data from a 5-month, placebo-controlled study have also shown that galantamine produces significant benefits on behavioural symptoms. The persistence and range of therapeutic effects produced by galantamine suggest that it may provide additional benefits for patients with AD.