The early prescribers of penicillin realised that antibiotics should be used wisely and as an adjunct to traditional surgical provision. They predicted that inappropriate use would increase sensitisation to the drug. National Health Service dentists prescribed almost 10% of antibiotics issued in NHS general practice in 2016 and an audit shows that many of these may have been prescribed inappropriately. One of the causes of antimicrobial resistance is over prescription of the drugs. This paper recalls the recommendations of some early users of penicillin, reports on the current prescription patterns of dentists in England, describes the mechanism of acquisition of anti-microbial resistance and discusses dentists' role in attempting to reduce the problem.