Abstract: A dry powder inhaler for delivering a dose of medicament for inhalation by a user, including a drug entrainment device and a valve actuable by a user to cause pressurised gas to flow through a dose of medicament disposed in the drug entrainment device to entrain said dose in the gas, the valve comprising a valve member (28) configured such that, in a first mode, pressurised gas biases the valve member (28) into an open state to allow the flow of gas through the valve and, in a second mode, pressurised gas biases the valve member (28) into a closed state to prevent the flow of gas through the valve.