The gut microbiome has many effects on host health and is known to play a role in inflammation; the metabolites produced by the gut microbiota have recently been shown to affect the blood-brain barrier (BBB). In this interview, Lesley Hoyles, PhD, CBiol, MRSB, of Imperial College London, London, UK, discusses her work in this area, which indicates a potential protective role of propionate on the BBB. This video was recorded at the Alzheimer’s Research UK Conference 2018, held in London, UK.