 Organometallic compounds containing mercury (e.g., thiomersal) and arsenic (e.g.Salvarsan) had a long history of use in medicine as nonselective antimicrobials before the advent of modern antibiotics.Titanocene dichloride displays anti-cancer activity, and Dichloridobis[("p"-methoxybenzyl)cyclopentadienyl]titanium is a current anticancer drug candidate.