['This study examined whether some of the age-associated decrements in basic cognitive resources (information-processing speed and working memory) result from anticholinergic medication use (as measured by serum anticholinergic activity [SAA]) and whether such decrements are lessened by caffeine.', 'Cross-sectional observational study.', 'University medical center.', 'One hundred fifty-two normal-elderly community volunteers.', 'Two tests each of information-processing speed and of working memory were administered, and blood samples were drawn before and after cognitive testing to determine serum levels of anticholinergic activity and of paraxanthine-a caffeine metabolite.', 'Elevated SAA was associated with a significant but modest slowing in information-processing time but only in those individuals who had low levels of serum paraxanthine. SAA did not correlate with performance on tests of working memory.'] Is cognitive slowing associated with elevated serum anticholinergic activity in older individuals decreased by caffeine use?