A device having a body (10), a reservoir (100) mounted to slide axially relative to the body, a metering valve (200) on the reservoir (100), a blocking element (500), a trigger element (600), an inhalation-controlled trigger system (60) cooperating with the trigger element, an actuating member (800) cooperating with the blocking element, a cover (11) fixed on the body, a push member (810) fastened tot actuating member (800) and mounted to slide axially in the cover, and a spring (850) between the cover and the push member. Before inhalation, the push member is out of contact with the reservoir, such that the force exerted on the push member by the spring is not transmitted to the reservoir, and during inhalation, the push member moves axially with the actuating member so as to come into contact with the reservoir and move it axially in the body to actuate said valve.