An inhaler, preferably for insertion into a nostril, in particular a horse's nostril, with an inhalation valve, which has a movable valve element, whereby the valve element is designed in an annular manner and has an outer edge and an inner edge, whereby the valve element is fastened at the outer edge, the inner edge forms the boundary of an indentation of the valve element, and the inhalation valve has a valve body seat that corresponds to the inner edge.