Mouth breathing is a common condition in many adults and can lead to dental and medical problems. Mouth breathing tends to dry out the mouth and lead to excessive plaque build-up on the teeth and gums. From a medical perspective, mouth breathers tend to bypass the nasal passages, which filter and clean out many toxins and irritants in the air before it hits your lungs. Mouth breathing can change the oxygen/carbon dioxide balance, which can lead to the production of mucous and the constriction of blood vessels. At night this can contribute to snoring and sleep apnea. If you are aware of mouth breathing, get some medical help, usually the ENT. Some things you can try at home: elevate your head when you sleep, frequently squirt into your nasal passages with saline spray, try the breath right strips, limit alcohol consumption and be aware of any food or environmental allergies that may trigger nasal congestion.