Based on the data from this study, in contrast to patients with effective treatment, the levels of IL-6, IL-1β, IL-8, BGP, and MMP-8 in patients with ineffective treatment went up, suggesting that IL-6, IL-1β, IL-8, BGP, and MMP-8 were abnormally high in GCF in patients with severe periodontitis who failed drug treatment. Here, CXCL8 is linked to periodontitis.