What causes bad breath even after brushing

Bad breath or breath that smells like feces or poop can be caused by many different things. Common causes of bad breath can include poor oral hygiene, sinus infection, vomiting, GERD, and other oral health issues. It is common for patients to have bad breath at some point in their life. It can be cause for concern when the issue is chronic and does not improve over time.

Some of the causes for bad breath are harmless, however, there are some issues which are serious and require treatment. Some of the most common causes of bad breath are summarized in the following article.

Poor Oral Hygiene

When patients neglect their teeth or do not have good oral hygiene practices, it can cause bad breath. The failure to brush and floss the teeth can result in bad breath because there is an accumulation of plaque and bacteria on the teeth and gums. When food and debris is not removed through flossing, it can cause breath which is quite unpleasant.

Another common cause for a foul odor in the mouth is gum disease. Gum disease is primarily caused by poor oral hygiene. When oral health is neglected, there is an overgrowth of bad bacteria which causes a bad odor in the mouth. Dentures and crowns should be cleaned just like natural teeth. The failure to practice good oral hygiene on a consistent basis can result in severe halitosis.

Bowel obstruction

An intestinal obstruction is a dangerous medical emergency which occurs when there is a blockage in the large or small intestine. This type of blockage in the intestinal tract can cause breath to smell like feces. Anything which is consumed during the obstruction will remain in the digestive tract and ferment. This can cause incredibly bad breath until the issue is resolved.

In addition to bad breath, below are other symptoms associated with an intestinal obstruction:
1. Reduced appetite
2. Bloating
3. Swelling, cramps, or pain in the abdomen
4. Constipation
5. Nausea and vomiting
6. Diarrhea
7. Unable to pass gas or a bowel movement


Vomiting which occurs over a long period of time can cause dehydration. Another symptom that comes along with this is bad breath from a dry mouth. Saliva is important as it cleans the mouth and helps reduce bad odor. Dehydration can cause a lower production of saliva.

Sinus Infection

Patients may have bad breath due to a sinus or respiratory infection. These types of infections can be caused by bronchitis, a viral cold, strep throat, or other health issues. Bacteria can move from the nose into the throat, causing a very bad breath odor. Below are other symptoms associated with a sinus infection:
* Thick, green or yellow nasal drainage
* Cold which lasts more than two weeks
* Low-grade fever
* Fatigue or irritability
* Postnasal drip with nausea, vomiting, cough, or a sore throat
* Eye swelling
* Headache

Gastroesophageal Reflux Disease (GERD)

GERD can be another common cause for bad breath. In some cases, it can cause the breath to smell like poop. This is due to the stomach acid flowing back up into the esophagus. The acid can cause irritation to the esophageal lining, resulting in severe discomfort.

Additional symptoms associated with GERD include the following:

1. Reflux occurring once or twice a week
2. Heartburn after eating or in the evening
3. Challenges with swallowing
4. Sour liquid or food regurgitation
5. Sensation of a lump in the throat
6. Laryngitis
7. Chronic cough
8. Asthma
9. Insomnia or issues with staying asleep

Patients with chronically bad breath should follow up with their dentist. The dentist can help identify the cause and work with the patient to create a treatment plan.

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