While Ayurvedic medicine has touted the cognitive enhancing effects ofBacopa monnierafor centuries, there is a need for double-blind placebo-controlled investigations. One hundred and seven healthy participants were recruited for this double-blind placebo-controlled independent group design investigation. Sixty-two participants completed the study with 80% treatment compliance. Neuropsychological testing using the Cognitive Drug Research cognitive assessment system was conducted at baseline and after 90 days of treatment with a special extract ofBacopa monniera(2 × 150 mg KeenMind) or placebo. TheBacopa monnieraproduct significantly improved performance on the ‘Working Memory’ factor, more specifically spatial working memory accuracy. The number of false-positives recorded in the Rapid visual information processing task was also reduced for theBacopa monnieragroup following the treatment period. The current study provides support for the two other published studies reporting cognitive enhancing effects in healthy humans after a 90 day administration of theBacopa monnieraextract. Further studies are required to ascertain the effective dosage range, the time required to attain therapeutic levels and the effects over a longer term of administration. Copyright © 2008 John Wiley & Sons, Ltd.