A supplemental oxygen delivery system is described in which Aerosol is delivered into a housing which sits in the circuit from the supplemental oxygen supply and optional humidifier. The supplemental oxygen passes through this chamber in which the aerosol is located, and collects the aerosol transporting it to a patient via a nasal cannula or a face mask. An aerosol generator is mounted to the housing and delivers aerosol into an oxygen stream flowing between an inlet and an outlet of the housing. The housing also has a removable plug in the base thereof for draining any liquid that accumulates in the housing. There is no disruption of oxygen delivery to patients using nasal cannulas who currently have to use a separate face-mask when receiving nebulized medication.