Introduction: Hydrogen peroxide (H2O2) used in dental procedures is an oxidant that caustic and may lead to chem-ical injury on oral mucosa exposed. The antioxidant and anti-inflammatory agent was required to prevent prolonged inflammation and inhibit the activity of free radicals to prevent tissue damage. Epigallocatechin-3 Gallate (EGCG) is an antioxidant class of polyphenol, isolated from green tea. Its anti-inflammatory effects could enhance wound healing. This study was to prove the potential role of EGCG in promoting oral mucosa wound healing. Reepitheli-alization is an essential process of wound healing used as a defining parameter of its success. Methods: The study was a randomized Post Test Only Control Group Design. 32 male Wistar rats (Rattus norvegicus) were divided into 2 treatment groups. 35% hydrogen peroxide applied topically using micro brush 2 mm of diameter on lower lip mucosa to induce the caustic ulcer. After 24 hours, the control group was given plain mucoadhesive placebo gel (CMC-Na), while the treatment group was given EGCG Gel 0.5%. Gels were applied topically on ulcer surface for 3 days. On the 5th day, rats euthanized for tissue sampling and histological specimens were made by HE staining. The present study measured epithelial cleft as the marker of epithelial formation by the morfometry method. The data were analyzed by independent T-test. Results: The mean of epithelial cleft at treatment group (549.25 ± 217.094 μm) was lower than the control group (1417.25 ± 180.572 μm), it was statistically different (p<0.05). EGCG enhanced reepithelialization through increasing expression of Transforming Growth Factor-beta 1 (TGF-β1) that stimulated migration and increased the adhesion strength of epithelial cells. Conclusion: It was concluded that EGCG gel 0.5% enhanced reepithelialization on oral mucosa wound healing.