The efficacy of licorice extract ( Glycyrriza glabra ) on growth and aflatoxin(s) production of  both  Aspergillus parasiticus and / or  Aspergillus flavus  were studied in Yeast Extract Sucrose medium ( YES ).Seventy two YES containing flasks were divided into 2 groups, the 1 st group of flasks were inoculated with a suspension of A.flavus containing 10⁶ spores, each, while the 2 nd group of flasks received similer count, each from A. parasiticus spores. Simultanousely, the licorice extracts were prepared at concentrations of 0.0, 0.1, 0.2, 0.4, 0.6, and 0.8 mg/ ml medium. Each group of flasks were divided into 6 subgroups to correspond the 6 studied concentrations of licorice extract. Consequently, each treated subgroup was divided into 2 equal number of flasks to be incubated at either 14 or 28⁰C. The parameters of mycelial dry weight, pH and aflatoxin(s) production were carried-out at the intervals of 3, 7, 10 and 30, 45 , 90 days in different treatments incubated at 14 or 28⁰C, respectively. Data showed an obvious inhibitory effect on both mould growth and aflatoxin(s) production at concentrations of 0.2 and / or 0.4 mg/ ml medium. Moreover, a lethal effect was obtained at concentrations 0.8 mg / ml medium in both A. flavus and A.parasiticus media,while the concentration of 0.6 mg/ ml medium showed lethal effect in media flasks previously inoculated with A. flavus only.