Aim: The aim of this study was to investigate the antitumor potential of guaiazulene-3-carboxylate derivatives against oral malignant cells. Materials and Methods: Twelve guaiazulene-3-carboxylate derivatives were synthesized by introduction of either with alkyl group [1-5], alkoxy group [6, 7], hydroxyl group [8, 9] or primary amine [10-12] at the end of sidechains. Tumor-specificity (TS) was calculated by the ratio of mean 50% cytotoxic concentration (CC ) against 3 human oral mesenchymal cell lines to that against 4 human oral squamous cell carcinoma (OSCC) cell lines. Potency-selectivity expression (PSE) was calculated by dividing TS value by CC value against OSCC cell lines. Cell cycle analysis was performed by cell sorter. Results: [6, 7] showed the highest TS and PSE values, and induced the accumulation of both subG and G /M cell populations in HSC-2 OSCC cells. Quantitative structure-activity relationship analysis demonstrated that their tumor-specificity was correlated with chemical descriptors that explain the 3D shape, electric state and ionization potential. Conclusion: Alkoxyl guaiazulene-3carboxylates [6, 7] can be potential candidates of lead compound for developing novel anticancer drugs. 50 50 1 2