In mice, deficiency of P‐gp at the BBB increases Aβ deposition.[134] In elderly non‐demented individuals, cerebral Aβ deposition has been demonstrated to be inversely correlated with P‐gp expression in the brain capillary.[135] In patients with AD, reduced P‐gp function has been observed compared to healthy controls.[136] Pregnane X receptor (PXR) agonist has been shown to increase P­gp expression specifically.[104] Upon treatment with PXR, AD model mice showed enhanced efflux of exogenous Aβ. Here, PGP is linked to Alzheimer disease.