The aim of this paper is to highlight a change in guidance relating to possible interactions between antibiotics and oral contraceptives. Until recently, dentists have been advised to warn women taking the combined oral contraceptive pill of the routine need to use additional contraceptive measures while taking courses of broad spectrum antibiotics. Recent guidance relating to this issue has changed and dentists may not be aware of this. This paper reminds dentists of the previous guidelines and related evidence, reviews the pharmacokinetics of hormonal contraception and presents them with the latest evidence-based guidance. This should change their clinical practice.