Introduction: The wood bark of Mezzetia parviflora Becc, has long served as one of the most important traditional herbal medicine sources in Buton Regency, Southeast Sulawesi. M. parviflora extracts were rich in polyphenols. This study was aimed to explore the lipid peroxidation inhibitory activity of polar extract of M. parviflora. Methods: The polar extract is the result of ethanol extract partition solved in acetone. The extract will keep polar components which are insoluble in acetone. Assayed methods applied are ß-carotene bleaching inhibition, thiobarbituric acid reactive substance (TBARS) measurement, and continuous monitoring of conjugated dienes formation in LDL. Results: M. parviflora extract inhibit ß-carotene/ linoleic acid oxidation, showed by IC50 value of 15.83 μg/ml in 30th minute; but the potency will be reduced to IC50 value of 111.19 μg/ml and 225.07 μg/ml after the 60th and 120th minute of incubation. M. parviflora extract inhibit MDA formation as for linoleic acid peroxidation product until the third day; at 20, 40, 60, 80 and 100 μg/ml inhibit MDA formation as many as 29.16 ± 2.41%, 4.24% ± 43.27, 54.08 ± 2.87%, 59.88 ± 1.90%, and 69.75 ± 2.32%, respectively. M. parviflora extract at 50 μg/ml can inhibit LDL-oxidation induced by CuSO4, performed by LDL-oxidation lag-time elongation until 70 minutes, similar ability was performed by epigallocathecin gallate at 5 μg/ml. Conclusions: M. parviflora extract expressed relatively strong protection against lipid and LDL oxidation which can serve as the scientific basis of its development as a remedy for various diseases caused by lipid peroxidation.