Morning breath happens because saliva drops overnight and bacteria in the mouth produce smelly sulfur compounds.
Why
Saliva flow drops during sleep. Dry mouth lets bacteria multiply. They break down proteins and release sulfur compounds that smell.
Increases
Mouth breathing, alcohol, smoking and garlic.
Fix
- Brush and floss before bed.
- Clean your tongue.
- Drink water in the morning.
- Use a humidifier.
Persistent
May signal gum disease, reflux or sinus infection.
See a dentist
If bad breath continues.
Mechanism
Morning breath comes from reduced saliva flow during sleep. Saliva normally washes away bacteria and food debris, and with less saliva anaerobic bacteria break down proteins on the tongue and in the gums into volatile sulfur compounds like hydrogen sulfide and methyl mercaptan.
- Sleeping with an open mouth dries tissues further.
- Alcohol, smoking, garlic and onion at dinner, and some medications increase odor.
- Sleep apnea and nasal congestion raise mouth breathing.
Fix
Brush teeth and tongue before bed, floss, and drink water before sleeping. Use a humidifier if the air is dry and treat nasal blockage. Chew sugar-free gum in the morning. If bad breath continues throughout the day, see a dentist to check for gum disease, cavities, and dry mouth, and a doctor for sinus problems, reflux or diabetes if no oral cause is found.
Mechanism
During sleep, saliva production drops, letting anaerobic bacteria on the tongue and throat produce volatile sulfur compounds such as hydrogen sulfide and methyl mercaptan. Breathing through the mouth worsens dryness. This is called morning breath and affects most people.
Fix
Brush teeth and tongue before bed and in the morning, floss, drink water and avoid alcohol late. Treat snoring or sleep apnea if present. See a dentist if bad breath persists all day, since gum disease or reflux may be involved.
Saliva and oral bacteria
Saliva flow falls to about 0.1 mL per minute at night, versus 1 mL per minute while awake. This lets anaerobic bacteria such as Fusobacterium and Porphyromonas multiply and release hydrogen sulfide and methyl mercaptan. Mouth breathing, alcohol the night before and medications that dry the mouth worsen it.
Reducing morning odor
Brush the tongue, use a floss, rinse with water before bed, run a humidifier and treat nasal congestion. Zinc containing mouthwashes neutralize sulfur compounds. Sugar free gum stimulates saliva. Persistent bad breath through the day suggests gum disease or other medical reasons. About 25 percent of people have chronic bad breath.
Based on data from the American Dental Association and the Cleveland Clinic
