Gallium (Ga) is an element. It is a soft, slivery blue metal that becomes liquid (and silvery white) above room temperature. Gallium has been investigated for its anticancer properties since it was discovered that 67Ga(III) citrate injected in tumor-bearing animals localizes to tumor sites. Gallium has been investigated for treatment in multiple types of cancer (bladder cancer, lymphoma, multiple myeloma, paget's disease, and prostate cancer). Different generations of gallium salt are being evaluated for their antitumor efficacy and are in preclinical or clinical development. Gallium might also display antimicrobial activity, and is thought to disrupt iron homeostasis in certain bacteria and fungi.