Interest in the medicinal properties of ruthenium(II)-arene compounds has grown rapidly over the last decade. In this account we describe the origins of the field and subsequently highlight developments in the field, including the design of compounds that inhibit enzymes, the application of multinuclear systems to act as drug delivery vehicles, and the development of bioanalytical and biophysical methods to help elucidate the mechanisms by which these compounds function. The conducive properties and reasons for the rapid growth in interest in these and related compounds for their medicinal applications, especially in the treatment of solid tumours, are identified. (C) 2013 Elsevier B. V. All rights reserved.