A metered-dose inhaler actuator, comprising: a housing having a mouthpiece portion and a canister receiving portion configured to receive a canister, said housing extending from an opening for receiving said canister to a mouthpiece opening; a member disposed within said housing and defining a valve stem receptacle configured to receive a valve stem of said canister, an orifice (16; 73, 74; 76, 77; 79, 80; 84; 88) for emitting an aerosol plume being formed in said member, said orifice (16; 73, 74; 76, 77; 79, 80; 84; 88) being in fluid communication with said valve stem receptacle and extending to a face of said member opposite to said valve stem receptacle; a longitudinal axis of said orifice (16; 73, 74; 76, 77; 79, 80; 84; 88) being aligned with a longitudinal axis of said valve stem receptacle; and at least one air inlet opening being provided in an outer shell of said housing so as to be spaced from said opening for receiving said canister and from said mouthpiece opening, said at least one air inlet opening being in fluid communication with said mouthpiece opening, and a longitudinal axis of said mouthpiece portion being arranged at an angle and not parallel relative to said longitudinal axis of said orifice (16; 73, 74; 76, 77; 79, 80; 84; 88), characterized in that an air inlet opening of said at least one air inlet opening is arranged to produce an airflow essentially perpendicular to the direction of the aerosol plume and is positioned on a line of view which passes through said mouthpiece opening and is aligned with said longitudinal axis of said mouthpiece portion, and is arranged to produce an airflow essentially perpendicular to the direction of the aerosol plume. a housing having a mouthpiece portion and a canister receiving portion configured to receive a canister, said housing extending from an opening for receiving said canister to a mouthpiece opening; a member disposed within said housing and defining a valve stem receptacle configured to receive a valve stem of said canister, an orifice (16; 73, 74; 76, 77; 79, 80; 84; 88) for emitting an aerosol plume being formed in said member, said orifice (16; 73, 74; 76, 77; 79, 80; 84; 88) being in fluid communication with said valve stem receptacle and extending to a face of said member opposite to said valve stem receptacle; a longitudinal axis of said orifice (16; 73, 74; 76, 77; 79, 80; 84; 88) being aligned with a longitudinal axis of said valve stem receptacle; and at least one air inlet opening being provided in an outer shell of said housing so as to be spaced from said opening for receiving said canister and from said mouthpiece opening, said at least one air inlet opening being in fluid communication with said mouthpiece opening, and a longitudinal axis of said mouthpiece portion being arranged at an angle and not parallel relative to said longitudinal axis of said orifice (16; 73, 74; 76, 77; 79, 80; 84; 88), characterized in that an air inlet opening of said at least one air inlet opening is arranged to produce an airflow essentially perpendicular to the direction of the aerosol plume and is positioned on a line of view which passes through said mouthpiece opening and is aligned with said longitudinal axis of said mouthpiece portion, and is arranged to produce an airflow essentially perpendicular to the direction of the aerosol plume.