Despite the extensive clinical use, eugenol is cytotoxic to various cell types though its mechanism of cytotoxicity has been unknown. Reportedly, eugenol reduced the growth of cells in vitro. Anpo et al. suggested that cytotoxic effect of eugenol can be associated with oxidative DNA damage by its metabilites. They also suggested that eugenol-related compound may act like non-steroidal anti-inflammatory drugs.18 In several studies, it has been stated that eugenol can inhibit neoplastic cell growth. Okada et al. demonstrated that eugenol induced apoptosis in oral tumor cells. Gosh et al. showed that eugenol could inhibit melanoma growth by inducing apoptosis and cell proliferation arrest. Their results showed eugenol is a potent inhibitor growth of melanoma cells, causes significant tumor growth delay, decreases size of tumor and inhibits melanoma invasion and metastasis. Eugenol arrests cells in the S phase of cell cycle, and induces apoptosis, and is not mutagenic. It has been shown eugenol is effective to inhibit papillomas.