A great many cardiovascular drugs (CVDs) have the potential to induce adverse reactions in the mouth. The prevalence of such reactions is not known, however, since many are asymptomatic and therefore are believed to go unreported. As more drugs are marketed and the population includes an increasing number of elderly, the number of drug prescriptions is also expected to increase. Accordingly, it can be predicted that the occurrence of adverse drug reactions (ADRs), including the oral ones (ODRs), will continue to increase. ODRs affect the oral mucous membrane, saliva production, and taste. The pathogenesis of these reactions, especially the mucosal ones, is largely unknown and appears to involve complex interactions among the drug in question, other medications, the patient's underlying disease, genetics, and life-style factors. Along this line, there is a growing interest in the association between pharmacogenetic polymorphism and ADRs. Research focusing on polymorphism of the cytochrome P450 system (CYPs) has become increasingly important and has highlighted the intra-and inter-individual responses to drug exposure. This system has recently been suggested to be an underlying candidate regarding the pathogenesis of ADRs in the oral mucous membrane. This review focuses on those CVDs reported to induce ODRs. In addition, it will provide data on specific drugs or drug classes, and outline and discuss recent research on possible mechanisms linking ADRs to drug metabolism patterns. Abbreviations used will be as follows: