The development of pharmaceutical agents possessing anti-invasive and anti-metastatic abilities, as well as apoptotic activity, is important in decreasing the incidence and recurrence of oral cancer. Cancer cells are known to acquire invasiveness not only through epigenetic changes, but also from inflammatory stimuli within the tumor microenvironment. Accordingly, the identification of agents that can suppress the inflammation-promoted invasiveness of cancer cells may be important in treating cancer and improving the prognosis of patients with cancer. Acetylshikonin, a flavonoid with anti-inflammatory activity, inhibits proliferation and induces apoptosis of oral cancer cells. In the present study, the anti-invasive effect of acetylshikonin on YD10B oral cancer cells infected with Porphyromonas gingivalis, a major pathogen of chronic periodontitis, and the mechanisms involved were investigated. Firstly, we examined whether P. gingivalis infection increased the invasiveness of YD10B cells. Results suggested that YD10B oral cancer cells become more aggressive when they are infected with P. gingivalis. Secondly, acetylshikonin significantly inhibited the invasion of P. gingivalis-infected YD10B cells by suppressing IL-8 release and IL-8-dependent MMP release. These data suggest that acetylshikonin may be a useful preventive and therapeutic candidate for oral cancer that is chronically infected with periodontal pathogens.