###Human: My son is breathing through mouth and not nose. What can I do for it? ###Assistant: Hi. You son is suffering from upper airway obstruction. It causes him to breathe through the mouth. It could be a result of allergies or inflammation of adenoids behind the nose. It can be cured by steroid sprays. It is just a part of the treatment. If there is some other form of inflammation of adenoids, then he needs removal of adenoids. If your son becomes unresponsive at any stage, then he needs surgery. Mouth breathing can also lead to a complex problem such as adenoid facies.