Flavour capsules in cigarette filters are a product design innovation that allows consumers to crush a liquid-filled capsule that flavours the cigarette smoke. Most capsules include menthol flavourings, with chemosensory properties including a cooling, anaesthetic effect that makes it easier to inhale cigarette smoke, promotes misperceptions of harm and increases the appeal of smoking for youth. Industry pretesting revealed the attractiveness of choosing if and when to crush the capsule for the flavour, but cautioned that this novelty may wear off. Nevertheless, since the initial introduction of flavour capsule cigarettes in the Japanese market in 2007, capsule brand variants have been introduced worldwide. Industry reports and independent research indicate a number of countries where market share for flavour capsule cigarettes has grown exponentially.