An inhaler (10) for the inhalation of inhalable substances comprise: a canister (50) having an interior reservoir (84) containing pressurised inhalable substances including fluid； a metering valve (52) including a metering chamber (82) and a valve stem (54) defining a communication path between the metering chamber and the interior reservoir, the communication path (86) including an opening (106) configured to permit flow between a transfer space inside the valve stem and the interior reservoir, the interior reservoir being arranged for orientation above the metering chamber whereby gas such as air located within the metering chamber is replaced with liquid from the interior reservoir.
