["To explore the effect of Ginkgo biloba extract (GbE) on the levels of caspase-3 and amyloid precursor protein (APP) in normal rats' hippocampus.", 'Immunohistochemistry method was used for qualitative analysis of the expressions of caspase-3 and APP, and an image analysis method was used for the quantification of the levels of caspase-3 and APP after GbE was administered to rats of different ages for 14 d.', 'The mean absorbance of staining of caspase-3 and APP was markedly higher in GbE group than that in control groups. The expressions of caspase-3 and APP were intensified in the hippocampus of rats after GbE administration.'] Does ginkgo biloba leaf extract enhance levels of caspase-3 and amyloid precursor protein in normal rat hippocampus?