Following a study in a mouse model of Alzheimer's disease showing positive results on Aβ and tau pathology obtained after FMT from control mice (Sun et al., 2019), Park et al. (2021) very recently exploited the FMT strategy in a person with Alzheimer's disease diagnosed with C. difficile infection. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.