Forty patients diagnosed as suffering from senile dementia of the Alzheimer type received either 80 mg Ginkgo biloba special extract (GBE)* or matching placebo t.i.d. for three months in a randomized, double blind study of the efficacy and tolerance of GBE. The patients were assessed using a test battery at baseline and at 1, 2 and 3 months. The test battery included the SKT (a brief test of cognitive function, memory and attention), the Sandoz Clinical Assessment Geriatric Scale, choice reaction time, saccadic eye movements and EEG. Memory and attention, as measured by the SKT, improved significantly in the active treatment group after one month, as did psychopathology, psychomotor performance, functional dynamics and neurophysiology as measured by the above tests. The drug was well tolerated and no adverse drug reactions were recorded during the trial.