There is increasing evidence that nonsteroidal and cholesterol lowering medications may be associated with a delay in the onset of Alzheimer's disease (AD). There is separate evidence that beta-amyloid(1-42) is involved in the pathophysiology of AD and levels of beta-amyloid(1-42) in the cerebrospinal fluid (CSF) of AD patients are significantly lower than that found in controls. It has been suggested that these standard medications may have indirect effects that alter the normal course of AD, but there is no data to directly support this contention in humans. Based on previous work, it is our hypothesis that CSF beta-amyloid(1-42) levels may serve as an early biomarker of AD. Any pharmacological induced change in CSF beta-amyloid(1-42) might have profound implications for the eventual onset of illness. Therefore, the purpose of this study is to evaluate the short-term effects of two commonly prescribed nonsteroidal and cholesterol lowering medications, ibuprofen and lovastatin, on the levels of cerebrospinal fluid beta-amyloid(1-42) in a group of normal controls 'at risk' for developing AD.