An editorial in this week's British Medical Journal highlights the growing problem of antibiotic resistance. Prof Sebastian Amyes, of the University of Edinburgh, suggests one problem is that no new classes of clinically useful antibiotics have been discovered since 1961. Almost all the drugs launched since the 1960s have been modifications of antibiotics we already have. Once bacteria learn to resist one member of a class of antibiotics, such as the penicillins, the later modifications also fall victim to resistance. The hope for the future is that an increased understanding of bacterial genetics will provide a solution to resistance.