Can acid reflux cause bad breath?

Acid reflux happens when the valve at the bottom of your esophagus lets stomach contents travel back up. When it happens often or causes complications, it is called gastroesophageal reflux disease, or GERD. The NHS lists bad breath among reflux symptoms, along with heartburn, an unpleasant sour taste, a hoarse voice and a cough that keeps coming back.

There are a few likely ways reflux affects your breath:

• Refluxed material itself. Partly digested food and acid reaching the throat or mouth smells sour.
• A coated tongue and dry mouth. A 2020 study of students with GERD found coated tongue, dry mouth and bad breath among the symptoms outside the esophagus. A thicker tongue coating gives odor-producing bacteria more to feed on.
• Throat irritation and mucus. Reflux that reaches the throat can cause throat clearing and a feeling of mucus, which may add to the smell.

People usually describe reflux breath as sour, acidic or like vomit, often with a matching sour taste that is worse after meals, when bending over or when lying down. That is different from the rotten-egg smell of sulfur gases made by tongue bacteria, though you can have both at once.

In a study of 132 patients at a gastroenterology clinic, bad breath was linked with heartburn, regurgitation, sour taste and belching, and was associated with GERD rather than with functional dyspepsia or stomach ulcers. The authors suggested bad breath can be one of the reflux symptoms that shows up outside the esophagus.

NIDDK lists several things that raise the chance of GERD: being overweight, pregnancy, smoking or secondhand smoke, a hiatal hernia, and some medicines such as certain sedatives, blood pressure drugs called calcium channel blockers, NSAID painkillers and tricyclic antidepressants. MedlinePlus adds alcohol and lying down within 3 hours of eating. Do not stop a prescribed medicine on your own; ask your doctor if you think it is making reflux worse.

Work on both the source and the mouth:

• Eat smaller meals and stop eating 3 to 4 hours before bed, per NHS advice.
• Raise the head of your bed by about 10 to 20 cm (4 to 8 inches) with blocks or a wedge under the mattress, rather than stacking pillows.
• Learn your triggers. Avoid the foods and drinks that set off your symptoms; alcohol is a possible trigger, but triggers vary from person to person.
• Stop smoking if you smoke.
• Keep your mouth clean. Brush twice a day, clean between teeth and clean your tongue daily so bacteria are not adding sulfur smells on top of the reflux.
• Rinse with water after a reflux episode to clear acid from your mouth.

Mints and mouthwash can mask the smell for a short time but do nothing for the reflux. Our guide to mouthwash for bad breath explains which ingredients do more than cover it up.

A pharmacist can recommend antacids or alginates for occasional heartburn. If symptoms continue, a doctor may prescribe acid-reducing medicine such as a proton pump inhibitor, usually for a set course, and may refer you for tests such as an endoscopy if symptoms are severe or unusual. MedlinePlus notes that long-term reflux can lead to complications including dental problems, a chronic cough or hoarseness, and changes in the lining of the esophagus, which is why persistent symptoms deserve a proper check.

See a GP or doctor if you have heartburn most days, if pharmacy medicines and lifestyle changes are not helping, or if you also have food getting stuck, frequent vomiting or weight loss without trying. If your breath is bad but you have none of the reflux symptoms above, see a dentist first, because most bad breath starts in the mouth. Our page on bad breath from the stomach covers other digestive causes.