Abstract: Various aspects described herein are directed to nebulizer assemblies for improving the effectiveness of the nebulizers. In some embodiments, instead of placing a nebulizer directly in-line with a first passageway connecting between a patient connector and a ventilator, nebulizer assemblies, in which the nebulizer is connected to a second passageway that extends upward from a top portion of the first passageway, are provided herein. Such configuration of the nebulizer assemblies can prevent a patient's secretion from clogging the nebulizer and thus improve the output of a drug delivered to the patient.