The aim of the study was to investigate the effects of continuing treatment with Ginkgo biloba extract (GBE) 120 mg/day on the activities of daily living (ADLs) and mood in healthy older volunteers who had immediately previously participated in a survey of the effects of a 4 month treatment with the drug. Following a prior postal survey investigating the effects of 4 months supplementation with GBE on ADLs and various aspects of mood and sleep, 1570 volunteers continued onto a 6 month follow-up postal survey. Subjects selected their own treatment option for the follow-up survey, which effectively created four groups: a continuation group who received GBE in the initial 4 month study and during the 6 month follow-up (GBE-GBE), a discontinuation group who received GBE in the initial study but not during the follow-up (GBE-NT), a new treatment group who did not receive GBE in the initial 4 month study but who did receive GBE during the 6 month follow-up (NT-GBE), and a no treatment group who received no treatment in either survey (NT-NT). At the end of the 6 month follow-up period each subject completed a line analogue rating scale (LARS) and a self-rating activities of daily living scale (SR-ADL). There were signi fi cant differences in the mean overall LARS and SR-ADL scores between the four treatment combination groups at the end of the follow-up period. A factor analysis of the LARS revealed two factors, 'mood' and 'alertness'. When scores from each of the treatment groups were examined over the whole 10 month period it was evident that the ratings of overall competence in the SR-ADL and both factors of the LARS were diminished on cessation of treatment with GBE, and improved when GBE treatment was initiated. The magnitude of the improvements on all scales was related to the overall duration of GBE supplementation.Signi fi cant differences between the groups of subjects treated with GBE for different periods of time (4-10 months) suggests that the extract has a demonstrable effect in improving mood and the self-assessed performance of the tasks of everyday living.