The study investigates the potential of *Faecalibacterium duncaniae* (formerly *F. prausnitzii*) as a next-generation probiotic against influenza. *F. duncaniae* is a butyrate-producing bacterium that has shown health-promoting characteristics. The researchers gavaged mice with live *F. duncaniae* (strains A2-165 and I-4574) five days before infection with a sub-lethal dose of influenza A virus (IAV). The results showed that *F. duncaniae* supplementation reduced body weight loss, decreased pulmonary viral load, and reduced lung and gut inflammation. *F. duncaniae* also impacted gut dysbiosis induced by infection, as assessed by 16S rRNA sequencing, and restored levels of short-chain fatty acids (SCFAs), including butyrate. The live form of *F. duncaniae* was more effective than the pasteurized form in improving influenza outcomes. Additionally, *F. duncaniae* partially protected against secondary bacterial infections. The study concludes that *F. duncaniae* could serve as a novel probiotic for managing acute viral respiratory diseases.The study investigates the potential of *Faecalibacterium duncaniae* (formerly *F. prausnitzii*) as a next-generation probiotic against influenza. *F. duncaniae* is a butyrate-producing bacterium that has shown health-promoting characteristics. The researchers gavaged mice with live *F. duncaniae* (strains A2-165 and I-4574) five days before infection with a sub-lethal dose of influenza A virus (IAV). The results showed that *F. duncaniae* supplementation reduced body weight loss, decreased pulmonary viral load, and reduced lung and gut inflammation. *F. duncaniae* also impacted gut dysbiosis induced by infection, as assessed by 16S rRNA sequencing, and restored levels of short-chain fatty acids (SCFAs), including butyrate. The live form of *F. duncaniae* was more effective than the pasteurized form in improving influenza outcomes. Additionally, *F. duncaniae* partially protected against secondary bacterial infections. The study concludes that *F. duncaniae* could serve as a novel probiotic for managing acute viral respiratory diseases.