Is unintentional doping real, or just an excuse? Although some athletes who engage in doping do so willingly in order to gain an unfair advantage (ie, ‘to cheat’), the possibility of athletes doping inadvertently or unintentionally cannot be discounted. In this article, we aim to address common misconceptions of the notion of ‘unintentional doping’, and discuss this topic with reference to statistics, reports and recommendations (eg, anti-doping codes) produced by the World Anti-Doping Agency (WADA), together with evidence from recent empirical research. Unintentional doping (also known as ‘inadvertent’ or ‘accidental’ doping) refers to the accidental consumption of performance-enhancing substances included on WADA’s banned list. It often occurs when an athlete uses a product (eg, nutritional supplements, ‘energy’ drinks or products, and medical, herbal or ‘natural’ products) that contains the banned substance or is exposed to the banned substance in routine situations (eg, drug smoke, hormone-tainted meat), while being unaware of the presence of the banned substance. However, it is acknowledged that unintentional doping is often used as an excuse by athletes to explain adverse analytical findings in doping control samples. WADA has adopted a near zero-tolerance policy when it comes to athletes claiming unintentional use. The relevant WADA statute notes that claiming a positive test is ‘attributed to the misuse of supplements and taking a poorly labelled dietary supplement is not an adequate defence in a doping hearing’. Only strong, non-circumstantial evidence is sufficient to exonerate an athlete claiming accidental doping during the post-transgression disciplinary process. Otherwise the athlete is considered to have violated anti-doping rules and will be served with the requisite penalty. … In conclusion, unintentional doping should be considered when developing strategies to prevent doping and transgression of WADA rules on banned substances. WADA’s policies make it clear that the onus lies largely on athletes and their support teams to be aware that banned substances might be present in the athletes’ diets and to take appropriate precautions. However, there is a dearth of evidence on how to effectively manage the prevention of unintentional doping. Formative research is needed to develop effective interventions to safeguard athletes from unintentional doping. These interventions should involve all stakeholders (eg, athletes, coaches, sport managers/organisations, practitioners of sport medicine, sport dieticians and doping control officers/agencies) in order to offer a collaborative educational and preventive programme for the prevention of unintentional doping. Chan DKC, Tang TCW, Yung PS, et al. Is unintentional doping real, or just an excuse? British Journal of Sports Medicine 2019;53:978-979. Is unintentional doping real, or just an excuse?