The ethanolic extracts (aerial parts and bulbs) of the Allium sphaerocephalon, has medicinal and food properties; these extracts were isolated, and its antibiofilm, mutagenic and antimutagenic activities were investigated. Minimum inhibitory concentrations (MICs) was calculated by broth microdilution method in microtiter plates against two Gram-positive (S.aureus and B.subtilis), two Gram- negative bacteria (E.coli and P.aeruginosa) and C.albicans. Antibiofilm effect of extracts was  evaluated by microtiter plate assay. The mutagenic and antimutagenic activities were investigated by Ames Salmonella/microsome mutagenicity test. The ethanol extracts of Allium sphaerocephalon were effective against all the strains tested, with minimum inhibition concentrations ranging between 3.125 and 50 mg/ml. MIC results showed that the aerial parts extracts had the strongest growth inhibition effect against C.albicans. The aerial parts extracts also were able to inhibit 54.18%, 24.06% and 10.27% of E.coli biofilm structure in concentrations MIC, MIC/2 and MIC/4, respectively.The ethanolic extracts can be considered genotoxically safe, because it does not have any mutagenic effect at the tested concentrations.  As a result, the ethanolic extracts of the Allium sphaerocephalon exhibited antimutagenic effect at 2.5 mg/plate concentration. Although the antioxidant capacity and inhibitory effects of Allium sphaerocephalon extracts/essential oils on planktonic bacteria have been investigated in a few studies, the antibiofilm activity and antimutagenic capacity of Allium sphaerocephalon ethanol extracts has not been reported to date. The aim of the present study was to investigate antibiofilm, mutagenic and antimutagenic activity of ethanol extracts of Allium sphaerocephalon.