In the present study, we investigated the potentials of erinacin A-enriched Hericium erinaceus mycelia (HE-My) and it ethanol extracts (HE-Et) on AD-related pathologies in 5 month-old APPswe/PS1dE9 (APP/PS1) double transgenic mouse, a transgenic mouse model of AD expressing two mutations in the human APP as well as two human presenilin 1, exhibiting impaired exploratory behavior, spatial memory and synaptic function [14–16]. The gene discussed is PSEN1; the disease is Alzheimer disease.