The discovery of penicillin is arguably one of the most important scientific discoveries of the 20th century. In the years following this discovery, it was assumed that we had conquered bacterial infections, and science moved onto other problems, such as combating viral infections. However, in recent years there has been a rise in infections caused by antibiotic-resistant bacteria. How do bacteria develop antibiotic resistance? How can inappropriate use of antibiotics and other antibacterial products contribute to this problem? What should we do to combat it?