A nebulizer for efficiently and reliably delivering aerosolized fluid to an inhaling patient is disclosed. The nebulizer, in one embodiment, includes a fluid channel air inlet and fluid channel air inlet valve responsive to either a manual force external of the nebulizer, or a patient's breathing, to begin the nebulization process. The nebulizer also includes a fluid return channel to a fluid source, such as a removable vial, containing fluid to be aerosolized.