Eli5: morning breath


How do people end up with bad morning breath even though we brush, floss and use mouthwash regularly.

In: Biology

Bad breath is a pretty normal part of being human, the reason we all worry about it so much is due to advertising by the listerine company trying to sell mouth wash.

When you sleep your saliva production slows down considerably and this allows bacteria to grow and that is what emits the odour.

No amount of brushing, flossing, or mouthwashing will kill every bit of bacteria or remove every last bit of food in your mouth, so overnight, many bacteria regrow and with your mouth going unused and pretty dry all night, they can flourish. They also live in plaque and release acid if you eat something, which can destroy your enamel.

Anaerobic bacteria (oxygen-hating) build up in your mouth at night, brushing disrupts the buildup of them. That’s why you get plaque, plaque is a bacterial mat, and when bacteria reach that critical mass they’ll start breaking your teeth down.

I’m lucky. When I brush my teeth I don’t have morning breath. But I would clean my tongue too.