Through an in-depth analysis of omics data, the key molecule C9 in the complement pathway was identified as the core regulatory target, establishing a pathological mechanism framework of "Staphylococcus aureus infection—complement cascade activation—C5a/C5aR1 axis-mediated inflammatory response." Experimental results demonstrated that YYJH effectively blocks the activation of the C5a/C5aR1 signaling axis by downregulating C5aR1 protein expression, inhibiting C5 cleavage, and reducing macrophage infiltration. The gene discussed is C9; the disease is staphylococcus aureus infection.