In conclusion, our work demonstrates that microbiota-derived butyrate alleviates allergic asthma via inhibiting Tfh13-mediated anaphylactic IgE production in a GPR43-dependent manner; we also propose the potential of butyrate and the HAMSB diet as a preventive and therapeutic approach for asthma (Fig. 7). This evidence concerns the gene FFAR2 and allergic asthma.