this research determines the antioxidant properties of the essential oils from aloysia triphylla (at) and minthostachys mollis (mm), their antioxidant activity in sunflower oil during accelerated storage (60 ^0c), and how this storage condition affects the volatiles profile of these essential oils. the main constituents of at essential oil are neral (27.3%), spathulenol (25.6%), and geranial (24.4%), whereas pulegone (53%) and menthone (29.5%) predominate in mm. both essential oils present minor modifications in the chemical compositions after storage at 60 ^0c for 14 days. the antioxidant activity is determined by the 2,2-diphenyl-1-picrylhydrazyl (dpph) free radical scavenging activity and monitoring the chemical and volatile oxidation indicators during accelerated storage of sunflower oil. the dpph results show 48.2% and 24.6% free radical inhibition for at and mm, respectively. in the accelerated oxidation test, the samples with 0.02% essential oil show the best antioxidant properties and are comparable to butylated hydroxytoluene. based on these results, at and mm essential oils show potential use as antioxidants in foods with high lipid content. practical applications : lipids are susceptible to oxidation associated with off-flavor generation, which decreases their quality and nutritional properties. natural antioxidants can be used as an alternative to replace synthetic antioxidants, like bht, tbhq, or bha. the results of this research demonstrate that the essential oils obtained from two aromatic-culinary plants (at and mm) have antioxidant activity and constitute potential additives for preserving the quality of lipid-rich foods. deciphering the antioxidant mechanism of these essential oils will promote interest in their use by the food industry. the current investigation shows the dynamics of lipid oxidation indicators in a lipid food matrix supplemented with these natural antioxidants. biplot of principal components analysis among samples and volatiles and chemical oxidation indicators. samples are sunflower oil control (s), sunflower with aloyzia triphylla (sa), and minthostachys mollis (sm) at different concentration (0.02%, 0.10%, and 0.20% essential oil in sunflower oil) and sunflower with bht as control (0.02%). biplot shows the antioxidant effect from both essential oil against lipid oxidation.