CDP-choline (cytidine-5-diphosphate-choline) is an acetylcholine precursor frequently used in cerebrovascular disorders and psychoorganic syndromes. Furthermore, several authors have demonstrated the positive effects of CDP-choline on cognitive disorders and memory deficits. In the present study, the effects of CDP-choline (1000 mg/day, p.o. for 1 month) on cognition, evaluated by the Mini-Mental State Examination (MMSE) of Folstein et al., and on blood flow velocities, measured by transcranial Doppler ultrasonography (TCD), were investigated in patients with Alzheimer's disease: (AD, n = 20, age: 66.75 +/- 6.73 years, range: 57-78 yr). Cognitive function was measured by means of the MMSE in basal conditions (A) and after 1 month of treatment with CDP-choline (C). TCD measures were taken through the temporal window for right (MCA-R) and left (MCA-L) middle cerebral arteries with a 2 MHz pulsed transducer using a TC-2000S in basal conditions (A), 1 h after the administration of CDP-choline (B) and after 1 month of treatment with CDP-choline (C). MMSE scores were significantly increased (p < 0.005) in patients with early-onset Alzheimer's disease (EOAD) after CDP-choline treatment. Moreover, the orientation subtest significantly increased in the global group of AD patients (p < 0.01) and in EOAD patients (p < 0.02). Significant differences (p < 0.05) were also found in MCA-Land MCA-R measures between recordings. These results suggest that CDP-choline influences cognitive and cerebrovascular function in Alzheimer's disease, probably through a mechanism linked to an immunogenic and/or neurotrophic effect at the microvascular niche.(ABSTRACT TRUNCATED AT 250 WORDS)