commercial plant extracts may act as antioxidants or prooxidants in cosmetic emulsions based on argan oil cosmetic emulsions containing plant extracts should be tested in a range of temperatures from 5c to 40c to be sure that they will be stable during general use by consumers and that plant extracts used as antioxidants do not accelerate oxidative degradation of their oil base the oxidative stability of argan oilinwater emulsions containing 1 and 5 commercial acerola willow and rose extracts or 001 butylhydroxytoluene bht stored at 5c and 20c for 6 months and at 40c for 4 weeks was monitored by the determination of peroxide content the antioxidant or prooxidant activities of extracts or bht in emulsions were expressed as the protection factor pf and inhibition of peroxide formation ip at the end of storage 5 willow 001 bht 1 willow and 5 acerola were the most protective for emulsions stored at 5c at 20c the most effective was 001 bht 5 rose and 5 acerola at 40c inhibition of peroxide formation calculated for 1 rose 5 acerola and 001 bht was similar altogether the results show that some plant extracts depending on storage conditions may act as prooxidants whereas the others can be applied as natural antioxidants instead of synthetic bht