An improved nebulizer breathing system wherein a supplemental gas may be introduced into the nebulizer head at a position after the liquefied medication has been fractured or nebulized, so that the introduction of the supplemental gas does not effect the rate at which the nebulized liquefied medication is applied to the user, and the mixture of gases to be administered to a patient is added to the breathing system at a position removed from the point at which the gas mixture is administered to the patient.