Recent research indicates a possible cholinergic involvement in memory processes and thus the possibility that acetylcholine deficiency may underlie memory impairment in senile dementia. Deanol (2-dimethylaminoethanol), which is assumed to increase brain acetylcholine, was given openly for 4 weeks to 14 senile outpatients, to determine the safety of the drug and whether or not it reduces cognitive impairment. The dosage was gradually increased to 600 mg three times daily during the first two weeks, with no adverse effects. Ten patients improved globally and 4 were unchanged (p less than .01). The total score on the Sandoz Clinical Assessment-Geriatric (SCAG) was lowered by the third week (p less than .01), primarily as a result of reduced depression, irritability and anxiety, and increased motivation-initiative. However, neither the clinical ratings nor an extensive pre- versus post-treatment series of cognitive tests revealed changes in memory or other cognitive functions. Since a similar separate study with a different compound produced no behavioral changes, it is unlikely that the improvement with deanol was due entirely to placebo effects. The results thus suggest that although deanol may not improve memory, it may produce positive behavioral changes in some senile patients.