Anaesthetists are generally familiar with the peri-operative implications of cigarette smoking. Although there are a number of publications dealing with the wider pharmacological implications of cigarette smoking, the specific interactions which are of direct relevance to anaesthetists are less well known. This review gives an overview of those interactions which are of clinical relevance to anaesthetists and provides, where possible, an explanation of the mechanism. Recent improvements in the understanding of biotransformation of drugs, including streamlining of the classification of hepatic enzymes has allowed better understanding of drug interactions and enables the mechanistic prediction of those involving new drugs.