The gut remembers: the long-lasting effect of medication use on the gut microbiome.

Growing evidence suggests that antibiotics and many human-targeted medications can alter the gut microbiome composition, but the persistence of these effects remains unclear. In their article, Aasmets and colleagues (O. Aasmets, N. Taba, K. L. Krigu, R. Andreson, et al., mSystems e00541-25, 2025, https://doi.org/10.1128/msystems.00541-25) leveraged electronic health records (EHR) and stool metagenomic data from 2,509 individuals to assess the impact of past medication use (up to 5 years prior to sampling) on the gut microbiome composition. They found that nearly half of the 186 tested drugs had long-term effects, with antibiotics, beta-blockers, benzodiazepine derivatives, proton-pump inhibitors, and antidepressants associated with microbiome changes that persisted for years after intake. For some medications, the effects were additive, with greater impact observed after repeated use. Overall, the authors highlight how medication use in the years preceding sample collection represents an often overlooked confounding factor in microbiome studies and emphasize the utility of combining EHR with microbiome data to assess the impact of past medication use.