Although both normal and Probio-M9-containing drinking water improved the disordered microbiome induced by AOM/DSS, Probio-M9 showed greater improvement in terms of not only the recovery of the numbers of destroyed bacteria (such as Muribaculum intestinale, Lachnospiraceae bacterium A4, and COE1) but also in the significance of changes in key bacteria (e.g., L. murinus and Parabacteroides goldsteinii). This evidence concerns the gene EBF1 and infectious otitis media.