A method and composition for treatment of bacterial infections caused by gram negative or gram positive bacteria such as Staphylococcus aureus, Rhodococcus equi, Mycobacterium tuberculosis, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Pseudomonas aeruginosa, Haemophilus influenzae, Proteus mirabilis, Enterobacter species, Serratia marcescens as well as those caused by Burkholderia cepacia, Stenotrophomonas maltophilia, Alcaligenes xylosoxidans, and multidrug resistant Pseudomonas aeruginosa, using a formulation containing gallium (III), in a pharmaceutically acceptable salt or complex thereof.