Research has shown that cigarette smoking can reduce fractional exhaled nitric oxide – or FeNO – by around 60%1but what about vaping? Electronic or ‘e-cigarettes’ have gained significant popularity in recent years as an alternative to traditional tobacco smoking. However, concerns have been raised regarding the potential impact on public health. One aspect of particular interest to the respiratory community is whether vaping affects FeNO levels. In this episode, we explore the evidence.