The extract enriched in total oligomer flavonoids (TOF), and the aqueous, methanol, and ethyl acetate extracts of Acacia salicina were investigated for their polyphenolic compound content, antioxidative activity in the nitro blue tetrazolium/riboflavin assay system, antibacterial activity against Gram-positive and Gram-negative bacterial reference strains, antigenotoxic activity tested with the Ames assay, and cytotoxic activity against the K562 human chronic myelogenous leukemia cell line and L1210 leukemia murine cells. TOF extract was effective at inhibiting nitro blue tetrazolium reduction by superoxide radical in a nonenzymatic $O_2^{cdot-}$-generating system. Significant activity against bacterial reference strains Staphylococcus aureus, Enterococcus faecalis, Salmonella enteritidis, and Salmonella typhimurium was shown with all the tested extracts. These extracts significantly decreased the genotoxicity induced by sodium azide and 4-nitro-o-phenylenediamine. A pronounced cytotoxic effect on both leukemia cell lines was detected in TOF, methanolic and ethyl acetate extracts. The antioxidant, antimicrobial, antigenotoxic, and cytotoxic activities exhibited by A. salicina depended on the chemical composition of the tested extracts.