In this study 10 patients affected with Alzheimer's disease (AD) and 10 from multiinfarct dementia (MID) were evaluated. After a 15-day wash out, patients underwent cognitive testing at baseline and after 6 months treatment with nicergoline (NIC 20 mg b.i.d.) or placebo (Pl b.i.d.), given according to a randomized double blind design. Brain MRI evaluation was performed at baseline and regional CBF was studied by using SPECT with 9 9 Tc-HM-PAD, at baseline and at the end of the study. The results of the clinical study revealed a significant improvement in MID patients treated with Nic., SCAG (Global Deterioration Scale for Dementia) subitems concerning affective disturbances improved by 34%; SCAG total score improved by 30%. Cerebral blood flow (CBF) studies showed a trend towards a reduction in the CBF interhemispheric asymmetries in MID patients treated with Nic, while no significant results were obtained in AD patients. No changes were recorded in both MID and AD patients after PL treatment. Such data indicate that further studies should be carried out in higher samples of patients to confirm these very preliminary results.