The present work describes the chemical composition and evaluates the antibacterial and the antioxidant properties of root oil from Ridolfia segetum, a traditional medicinal plant widely distributed in Tunisia. The essential oil, analysed by combination of GC, GC/MS and (13)C-NMR, was dominated by dillapiole (47.4%) and myristicin (19.2%). The antioxidant potential of the essential oil was evaluated using the 2,2'-diphenyl-1-picrylhydrazyl free radical scavenging method. The phenylpropanoid-rich root oil possesses good antioxidant properties (IC(50) = 38 mg mL(-1)). The essential oil was evaluated for its antibacterial activity using the microdilution assay, resulting in the inhibition of a number of common human pathogenic bacteria as well as of some clinical and environmental isolated strains. The minimum inhibitory concentrations of the essential oil varied between 1.25 and 5 mg mL(-1) and the minimum bactericidal concentrations were superior to 5 mg mL(-1) of oil for most strains. These results may suggest that the root oil of R. segetum possesses compounds with antibacterial and antioxidant capacities, and therefore can be explored as a natural preservative ingredient in food and/or for pharmaceutical preparations.