The chaoolmugra oil is one of the oldest medicines used for leprosy until the development of sulfas. In Brazil, it is known as sapucainha oil that is obtained from Carpotroche brasilienesis seeds (Flacourtiaceae). Chemical and medicinal studies of sapucainha oil were introduced in Brazil by Peckolt, Cole and Cardoso which showed that major ciclopentenyl fatty acids as chaulmoogric, hydnocarpic and gorlic were responsible for its bactericidal activity. In this work, a method for quantification of sapucainha oil acidic fraction by HRGC was established using methyl n-heptadecanoate as internal standard. The oil chemical stability was investigated by the use of GC-MS, IR, ¹H and 13C NMR and showed that the main degradation products belong to the cyclopentenyl moiety oxidation.