Why is it that we get bad breath after falling asleep?

Possible reflux: Assuming that your breath is fresh and clean smelling during the day then you may have a problem with gastric acids and reflux. This is common with people who snore and includes the possibility of apnea. Consult both your physician and dentist. More questions about your health history need to be answered.

Reduced saliva: When we sleep our salivary glands go into slow mode, producing about half the saliva they produce while we are awake. Food debris caught around teeth, especially between teeth where toothbrush can't reach begin giving off sulfurs. Make sure to floss daily. Have tonsils checked. Make sure gerd is not a problem. Brush teeth thoroughly before bed, and brush tongue lightly.

HOMECARE: Brushing and flossing is essential both in the morning and before bed! any food debris or plaque containing bacteria left behind overnight will lead to bad breath (morning breath) because the bacteria present, although not visible, cause decay of tissue. If that tissue is only food debris left behind then it is easily fixed. So brush and floss thoroughly in the morning and before bed to avoid this.

Many possibilities-: First, there is reduced salivary flow so less of the bacterial waste products are washed away. Second, you may suffer from GI problems such as acid reflux which would be more likely when you are lying down. Third, you may not be cleaning your teeth as well as you think, especially if you don't floss adequately or use a tongue blade. Finally, you may have sinus problems and post nasal drip.