An inhaler comprising a reservoir (2) of an inhalable composition. A valve element (11) moved by a flexible diaphragm (14) and biased into a position in which it closes a composition flow path from a reservoir. A first air flow path (16) is partly defined by one side of the diaphragm and a second air flow path (17) is partly defined by the opposite side of the diaphragm. Each flow path has an outlet (19, 21) opening at an outlet end and the second flow path has an inlet (20) upstream of the outlet end. The air flow paths (16, 17) are arranged such that suction at the outlet end causes a reduction in pressure in the first air flow path relative to the pressure in the second air flow path creating a pressure differential across the diaphragm (14) that moves the valve element (11) against the biasing force to open the composition flow path.一種吸入器包含了可吸入性結構的貯槽(2)。閥門元件(11)由彈性隔片(14)移動並且偏向使得閥門元件關閉來自於貯槽的混合物流動路徑的位置。第一空氣流動路徑(16)由隔片的一側所部分地界定，以及第二空氣流動路徑(17)由隔片的對立側所部分地界定。各流動路徑具有出口(19，21)，出口開口在出口端，而第二流動路徑具有入口(20)，入口係出口端的上游。空氣流動路徑(16，17)被如此排列，以致於出口端的吸力使得第一空氣流動路徑的壓力相對於第二空氣流動路徑的壓力有所減少，產生橫過隔片(14)的壓力差，此壓力差移動閥門元件(11)以抵抗偏向力並開啟混合物流動路徑。
