There is disclosed inhaler testing apparatus, in which at least one flow regulation valve, such as a needle valve, is located within a conduit. The flow regulation valve divides the conduit into inlet and outlet sides of the valve. The inlet side is arranged for connection to an inhaler and the outlet side for connection to a vacuum source. An electric motor provides variable adjustment of a flow opening through the valve. At least one sensor senses pressure or flow rate in the inlet side and a controller automatically adjusts the flow opening through the valve in response to readings from the at least one sensor. The apparatus may also comprise a shut off valve, such as a solenoid valve.
