the presence of mycotoxins as a result of fungal attack can occur before, after and during the harvest and storage operations on agricultural crops and food commodities. considering the inhibitory property of essential plant oils on the mycelial development of fungi and the importance of aspergillus flavus, the main producer of aflatoxins, this research was designed to evaluate the toxicity of essential oil from pittosporum undulatum against a. flavus. the essential oils were obtained from p. undulatum leaves, collected in different months and analyzed by gc/ms. the oils were rich in hydrocarbon, monoterpenes and sesquiterpenes and it was observed a significant variation on the chemical composition of the essential oil of leaves at different months. besides, the essential oils were tested against fungal growth and the results showed different spectrum of inhibition on a. flavus. however, the essential oils inhibited the aflatoxin b1 production.