The effects of two Iranian medicinal plants including Zataria multiflora and Geranium pelargonium
were evaluated on growth-inhibiting of some toxigenic fungi such as Aspergillus flavus, A. parasiticus, A.
ochraceus and Fusarium verticillioides. In this study, standard Z. multiflora and G. pelargonium essential
oils (EOs) were diluted in 0.01% dimethyl sulfoxide. Different dilutions of Z. multiflora (500, 1000, 2000
and 4000 ppm) and G. pelargonium EOs (1000, 2000, 4000 and 8000 ppm) along with 0.1 ml of each fungal suspension were inoculated onto sabouraud glucose agar and incubated at 25°C for 7 days. Zataria multiflora (≥2000 ppm) and G. pelargonium (≥8000 ppm) EOs completely inhibited all the tested fungi. Aspergillus species were more susceptible than F. verticillioides to two EOs. The EOs considerably exhibited inhibitory effects against these important toxigenic fungi and their different concentrations demonstrated various degrees of growth inhibition. This study showed inhibitory effects of Z. multiflora and G. pelargonium EOs against some toxigenic fungi including A. flavus, A. parasiticus, A. ochraceus and F. verticillioides.