The many activities of metal ions in biology have stimulated the development of metal-based therapeutics. Cisplatin, as one of the leading metal-based drugs, is widely used in treatment of cancer, being especially effective against genitourinary tumors such as testicular. Significant side effects and drug resistance, however, have limited its clinical applications. Biological carriers conjugated to cisplatin analogs have improved specificity for tumor tissue, thereby reducing side effects and drug resistance. Platinum complexes with distinctively different DNA binding modes from that of cisplatin also exhibit promising pharmacological properties. Ruthenium and gold complexes with antitumor activity have also evolved. Other metal-based chemotherapeutic compounds have been investigated for potential medicinal applications, including superoxide dismutase mimics and metal-based NO donors/scavengers. These compounds have the potential to modulate the biological properties of superoxide anion and nitric oxide.