The leaves essential oil of Tetraclinis articulata (Vahl) Masters was analyzed by GC and GC-MS, and then tested as corrosion inhibitor of carbon steel in 0.1 N of HCl, H2SO4 and HNO3, using electrochemical polarization method. It was also screened for possible biological activities especially antioxidant, antimicrobial, anti-5-lipooxygenase and anti-xanthine oxidase activities. Thirty-five components were identified, accounting for 96.6% of the total essential oil. The major components were Î±-pinene (29.0%), bornyl acetate (25.5%), camphor (16.6%) and limonene (6.7%). The corrosion rate of carbon steel decreased in the presence of the essential oil giving increased inhibition efficiency with increasing essential oil concentration. Polarization curves showed that this essential oil behave as mixed-type inhibitor with dominated cathodic character in the studied acidic media. The investigated essential oil showed substantial antimicrobial activity, which S. aureus was found to be the most sensitive bacteria. Also, this essential oil showed substantial antiradical and reduction activities. In addition, the 5-lipooxygenase and xanthine oxidase were efficiently inhibited by the tested essential oil. According to these finding, this essential oil may be suggested as new green inhibitor agent against corrosion in acidic media and could be considered as a potential natural antioxidant alternative for use in food industry.