According to the amyloid hypothesis, accumulation of amyloid β‐peptide (Aβ) in the brain is the primary pathogenic event in Alzheimer's disease (AD). Recent evidence indicates that Aβ within the intravascular space is linked to Aβ deposited in the brain suggesting that transport of Aβ between the brain, blood and cerebrospinal fluid, and across the blood–brain barrier, regulates brain Aβ. Thus, understanding Aβ exchanges between brain and blood, and vice versa, and developing transport‐based systemic Aβ‐lowering strategies may provide new important insights into pathogenesis and therapeutic control of AD.