While bad breath is usually just a bothersome side effect of the day’s lunch, breath that smells like poop can indicate a serious underlying condition.

From a bowel obstruction to an abscessed tooth, there are several potential causes of a feces-like odor on the breath.

In this article, we provide detailed descriptions of the six most common causes. We also discuss when to see a doctor.

1. Poor oral hygiene

Man using a breath freshener because his breath smells like poop
Poor oral hygiene may lead to breath that smells like poop.

Strong-smelling food is not always the cause of bad breath. Poor oral hygiene can lead to severe bad breath, even breath that smells like poop.

Factors that contribute to inadequate oral hygiene include:

  • infrequent cleaning
  • chronic dry mouth
  • inflammation or irritation of the mouth, nose, and throat
  • medications that cause dry mouth
  • oral infections
  • smoking or chewing tobacco

If a person has improved their oral hygiene routine and taken over-the-counter treatments and bad breath persists, they should see a doctor.

2. Sinus infection

The sinuses are air-filled passages in the face. When fluid becomes trapped in the sinuses, bacteria can collect, and this may lead to infection.

The presence of bacteria and excess mucus in the sinuses can lead to breath that smells like poop.

Additional symptoms of a sinus infection include:

  • post-nasal drainage
  • a poor sense of smell
  • a cough that often brings up mucus
  • facial pain and pressure
  • fatigue
  • a fever
  • a runny nose

Viruses cause most sinus infections, so antibiotics are not typically prescribed unless a doctor suspects a bacterial infection. Symptoms usually resolve within a few days with rest and fluids.

Anyone who experiences chronic sinus infections should speak with a doctor to determine the underlying cause.

3. Gastroesophageal reflux disease

Man holding chest due to acid reflux
GERD may cause the breath to smell like poop when the stomach acid mixes with food and possibly bacteria.

A doctor diagnoses gastroesophageal reflux disease (GERD) when a person frequently experiences acid reflux. This involves stomach acid backing up into the food pipe, or esophagus.

GERD can cause bad breath when the stomach acid mixes with food and possibly bacteria.

Additional symptoms of GERD include:

  • a burning sensation in the chest or throat commonly referred to as heartburn
  • difficulty swallowing
  • dental decay
  • nausea
  • respiratory problems
  • vomiting

GERD is a chronic condition that can lead to problems with the stomach, breathing, and teeth. Anyone who experiences frequent acid reflux should seek medical care.

4. Abscessed tooth

An abscessed tooth is a severe dental infection. It occurs when the pulp inside the tooth decays.

This may lead to a bacterial infection, which can result in pain, swelling, and breath that smells like feces due to a buildup of pus.

An abscessed tooth may not have painful symptoms until the infection is very advanced. A person should see a dentist for regular checkups, even when they have no symptoms.

To treat an abscessed tooth, a dentist may recommend a root canal, endodontic surgery, or a procedure to remove the tooth.

5. Prolonged vomiting

Anyone who has been vomiting for more than 24 hours may find that their breath smells sour and like feces. The odor is often caused by a combination of:

  • dry mouth
  • the acidic contents of the stomach, which have passed through the mouth
  • the bacteria or virus causing the vomiting

Vomiting is one way to get rid of toxins, but there is a limit to how much vomiting is healthy.

If a person cannot keep down any fluids or foods or has been vomiting for more than 48 hours, they should seek emergency medical treatment. They may need intravenous fluids to treat or prevent dehydration.

6. Bowel obstruction

young woman lying on the sofa who wants to know how to get rid of nausea
A person with a bowel obstruction may also experience abdominal pain, nausea, and vomiting.

A bowel obstruction occurs when the small or large intestine is blocked and can no longer move digested food through the body.

When an intestine is blocked, stool backs up, which can lead to breath that smells like poop. In severe cases, a person may even vomit feces.

A tumor, poor intestinal mobility, or scarring from surgery can all lead to bowel obstructions. In other cases, an obstruction may be caused by a problem with the intestinal wall, which can result from Crohn’s disease. Swallowed objects can also block the intestines.

In addition to foul-smelling breath, a person with a bowel obstruction may experience:

  • abdominal pain
  • abdominal bloating
  • an inability to pass gas
  • nausea
  • a rapid heart rate
  • vomiting

Bowel obstructions are serious and sometimes life-threatening. Anyone who suspects that they have an obstruction should seek immediate medical care.

After conducting a physical exam, a doctor will likely order imaging, such as a (CT) scan, to have a better view of the bowels and determine the cause of any obstruction.

It may be necessary to insert a tube through the nose into the digestive tract to remove excess gas from the intestines and stomach. This can alleviate symptoms and may eliminate the need for surgery.

However, severe bowel obstructions, such as those caused surgical scarring, may require surgery to remove the obstruction. A doctor may also have to remove a section of bowel.

When to see a doctor

A person should seek emergency treatment if they have vomited feces or suspect a bowel obstruction.

A person should also seek immediate medical care if they have:

  • a fever of more than 101.5°F (for adults) or 100.4°F (for children)
  • loss of consciousness or a change in mental status, such as extreme confusion
  • severe pain or discomfort
  • been vomiting for more than 48 hours
  • an inability to keep down fluids

Speak to a doctor if signs of infection are present or if symptoms do not improve over time.

If a person suspects that poor dental hygiene or an abscessed tooth is causing breath that smells like feces, they should make an appointment with a dentist.