Mice colonized with Rothia bacteria had less-severe allergic reactions to peanuts than did uncolonized mice. Credit: Kateryna Kon/SPL Bacteria in saliva and the small intestine might help to shield their host from severe allergic reactions to peanuts, a study1 in mice shows. Access Nature and 54 other Nature Portfolio journals Get Nature+, our best-value online-access subscription $32.99 / 30 days cancel any time Subscribe to this journal Receive 51 print issues and online access $199.00 per year only $3.90 per issue Rent or buy this article Prices vary by article type from$1.95 to$39.95 Prices may be subject to local taxes which are calculated during checkout doi: https://doi.org/10.1038/d41586-026-00668-9 Sánchez-Martínez, E. et al. Cell Host Microb. https://doi.org/10.1016/j.chom.2026.02.013 (2026).…