This study investigated the antibacterial effects of GR ethanol extracts (GRE), sodium chlorate (SC) and a combination of GRE and SC (GS) on Brucella abortus (B. abortus). The antibacterial activities of GRE, SC and GS towards B. abortus were evaluated by incubating B. abortus with GRE, SC and GS. Following treatment with GRE, SC and GS, B. abortus survival and intracellular proliferation in macrophages were monitored. In the cellular cytotoxicity assay, GRE, SC and GS are not cytotoxic at concentrations less than $400{mu}g/ml$, 15 mM and 0.6GS (1 of GS, GRE $1,000{mu}g/ml$ + SC 30 mM), respectively. The viability of B. abortus was markedly decreased in a dose-dependent manner in all treatment groups. In addition, B. abortus intracellular proliferation within macrophages was significantly reduced in cells treated with GRE ($400{mu}g/mL$), SC (15 mM) and 0.5GS (GRE $500{mu}g/mL$ + SC 15 mM) after 48 hr-incubation (GRE, p < 0.01; SC and 0.5GS, p < 0.001). Especially, in the treatment of GS, the synergistic effect of GRE and SC treatment on B. abortus in macrophage was observed. In conclusion, GS is useful as an antibacterial candidate against B. abortus, and can be applied in the field of meat and milk hygiene.