The present invention is directed to a mixing system for an active agent delivery device. The device comprises an elongate tubular member having first and second ends and a mixing system. The mixing system enables the entire dose of active agent to be entrained in a liquid. In use, liquid is drawn into the first end of the device, the mixing system mixes the liquid and active agent within the device and the active agent entrained in the liquid is drawn out of the second end of the member and into the patient's mouth.