Allylpyrocatechol (APC) which consists of benzene ring with hydroxyl groups, is a major phenolic constituent in Piper betle L. leaves extract. Antimicrobial activity of APC against S. aureus (ATCC 25923) was tested by determination of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) using the broth microdilution method. In addition, oxidative stress resistance assay was performed to determine the antioxidant activity of APC against hydrogen peroxide (10 mM), diamide(10 mM) and methyl viologen (10 mM) in relation to its toxicity against S. aureus. MIC and MBC values of APC against S. aureus were both 2000 µg/ml. Exposure of S. aureus cells to hydrogen peroxide, diamide and methyl viologen for 1 hour caused reduction of cells with percentage of survival of 87%, 15% and 10% respectively. Treatment of S. aureus cells with APC was found to increase killing compared to treatment with oxidative stress agent alone. Further research is recommended to investigate the effect of oxidative stress induced by hydrogen peroxide, diamide and methyl viologen on the production of reactive oxygen species (ROS) and antioxidant enzyme activities in S. aureus to elucidate the mechanism involved. This study potentially leads to discover and develop new antibiotic agents against all types of MRSA and in particular, novel phytochemicals of antimicrobial potential from natural products.