In this study 26 healthy volunteers received scopolamine 0.7 mg subcutaneously on seven occasions at least a week apart. Cognitive efficiency was measured with a test battery before and 60 min following scopolamine on each occasion. Following this, over the seven occasions, a range of oral and intravenous dose regimens were administered including aniracetam 2 mg intravenously, 100 mg intravenously, 200 mg intravenously, 1500 mg per os and piracetam 2400 mg per os. On each session the test battery was then performed again at 120 and 200 min following scopolamine. The seven treatments were administered double- blind and the order was counterbalanced between volunteers over visits using a Latin Square design. At 60 min, scopolamine produced marked and significant decrements in all of the measures of memory and information processing. Aniracetam 1500 mg was able to sig nificantly antagonize decrements on both memory and information processing tasks. The other active treatments also produced significant effects, but for two these were equal to, and for two slightly above, the number which may have occurred by chance, and thus were questionable. Overall, the findings demonstrate that aniracetam 1500 mg can antagonize cognitive decrements produced by cholinergic blockade in healthy volunteers, and suggest that the drug possesses nootropic properties.