Blood in Mouth – Causes of a Bloody Mouth

A bloody mouth does not always mean that the bleeding is from within the mouth. Since the mouth connects via throat to the nose, esophagus and airways, blood from these areas can easily reach the mouth. A bloody mouth can sometimes be a minor condition like a bleeding tooth cavity while at other times it may due to serious conditions like tuberculosis (TB) and cancer. The blood may appear as gross bleeding where blood itself collects in the mouth, or it may be mixed with saliva and mucus like in bloody phlegm or sputum.

Causes of Blood in the Mouth

The causes of blood in the mouth can be better understood by the different sites of bleeding – the mouth, nose, airways and lungs or esophagus. It is sometimes difficult to identify the cause of mouth bleeding and the presence of other signs and symptoms may be useful in diagnosing the underlying cause. Large volume bleeding from the mouth, especially if it continuous or worsening, should be treated as a medical emergency.

Oral Bleeding (Mouth)

Injury to the mouth itself is among the more common causes of bleeding in the mouth. A blow to the face, particularly to the mouth, may lead to a bloody mouth within seconds. Injury can also occur with dental surgery and even brushing too vigorously especially in the backdrop of gum diseases like gingivitis. Other causes of bleeding in the mouth may be linked orodental diseases including:

  • Bleeding ulcers (open mouth sores) often arises with severe injury inside the mouth where wound fail to heal and when infections set in.
  • Infections of the mouth may be due to a host of different pathogens including bacteria, viruses fungi and even some protozoa. Bleeding is more likely to occur with severe infections.
  • Stomatitis simply means inflammation of the mouth. It can arise for a number of different reasons including mechanical and chemical injury to the mouth, infections and autoimmune diseases.
  • Orodental diseases like a ‘rotting tooth’, dental abscess, gingivitis (gum disease) and periodontitis may all present with bleeding depending on the severity of the condition.
  • Scurvy is an uncommon condition these days but arises due to a vitamin C deficiency. Bleeding from the mouth and especially from the gums is a common symptom of scurvy.
  • Cancer of the mouth or throat is common especially among smokers and people who chew tobacco or areca nut. Sometimes the tumor may bleed.
  • Bleeding tonsils are usually indicative of very severe tonsillitis. Bleeding may also occur after tonsil removal surgery (tonsillectomy) but is usually short term and avoided by minimally-invasive procedures.
  • Poisoning can also cause bleeding from the mouth. Caustic substances may cause tissue damage and bleeding within the mouth while poisoning with heavy metals can eventually lead to bleeding from the orifices.

Nasal Bleeding (Nose)

Any cause of nasal bleeding (epistaxis) may also lead to blood being expelled from the mouth. The blood flow into the back of the nasal passage can pass into the nasopharynx and then into the mouth. In very rare cases, there may be erosion of the palate resulting in direct communication between the oral and nasal passages.

  • Trauma to the nose leading to bleeding is more likely to occur with a blow to the nose. Vigorous nose picking, overuse of nasal sprays, nasal inhalation of drugs and the insertion of foreign bodies into the nose are some of the more likely causes of injury. In severe cases, head injury can cause bleeding from in and around the brain to leak into the nasal cavity.
  • Rhinitis is inflammation of the nasal cavity. It is more commonly due to infections or allergies. Nasal bleeding due to rhinitis is usually seen in severe cases. Post nasal drip is where the mucus from the nose passes into the back of the throat.
  • Dry air is not often thought of as a cause of epistaxis but extensive drying of the nasal passages can make it prone to injury and bleeding. Usually the bleeding is minor.
  • Hypertension can also lead to rupturing of the tiny nasal blood vessels. Contrary to popular belief this is not a common occurrence in hypertension (high blood pressure).


A number of throat conditions that results in bleeding can cause blood in the mouth. The throat (pharynx) is directly connected to the mouth (oropharynx).

  • Trauma to the throat may occur with foreign bodies, diagnostic procedures, surgery, chemical injuries from corrosive substances or with acid reflux, and electromagnetic injury like during radiation therapy to the head for the treatment of cancer.
  • Infections of the throat (pharyngitis) or tonsils (tonsillitis). There are a host of bacterial, viral, fungal and certain protozoal infections that can lead to bleeding.
  • Abscess in the throat that may rupture and release pus and blood.
  • Cancer of the throat may also present with bleeding and like mouth cancer it is more often associated with cigarette smoking and tobacco chewing.

Respiratory Bleeding (Airways and Lungs)

The lower airways and lungs may at times be the source of bleeding and this blood may be coughed up into the mouth. This includes bloody sputum and in rare cases even gross bleeding from the respiratory tract and lungs into the throat and mouth.

  • Injury to the airways and lungs caused by mechanical, chemical or electromagnetic trauma.
  • Infections of the airways or lungs like laryngitis, tracheitis, bronchitis and pneumonia.
  • Foreign body lodged in the airways or lungs often associated with choking.
  • Pulmonary embolism where a clot blocks the blood vessels to the lungs.
  • Cancer of the airways or lungs which is more frequently seen in cigarette smokers.

Esophageal Bleeding (Food Pipe)

The throat leads to the esophagus and airways. The epiglottis is a small flap that closes off the airways when necessary, like during drinking or eating. Esophageal conditions that lead to bleeding may also result in blood in the mouth if the blood does not pass into the stomach and then into the rest of the digestive tract.

  • Infections of the esophagus.
  • Injury and tears.
  • Esophageal ulcers, often seen with acid reflux.
  • Cancer of the esophagus.
  • Dilated portion of the blood vessels (varices) that rupture.


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