We report results of a double-blind, 13-week trial of the alpha2 noradrenergic agonist guanfacine in 29 patients meeting clinical criteria for probable Alzheimer's disease (AD). Patients studied were relatively young (mean = 71 years), well educated (mean = 13.5 years), and in the early stages of cognitive deterioration (mean Mini-Mental State score = 22). We found no evidence of improvement with a single .5-mg daily dose of guanfacine and some evidence of a modest negative effect of the drug on neuropsychological tests. We concluded that noradrenergic intervention alone is unlikely to be effective in Alzheimer's disease.