Why Am I Spitting Out Blood?: A Guide to Causes and When to See a Doctor

October 1, 2025 •

4 min read

While the sight of blood in your saliva or sputum can be alarming, it's often a symptom of a treatable condition. Understanding why am I spitting out blood and identifying the source, whether from the mouth, throat, or lungs, is the crucial first step toward proper diagnosis and care.

Quick Summary

This article explores the potential causes of spitting blood, from common dental issues and respiratory infections to more serious conditions like lung cancer or blood clots. It details how doctors differentiate between potential sources of bleeding and outlines when to seek urgent medical attention for this symptom.

Key Points

Source Matters: Determine if the blood is from your mouth/gums, lungs (respiratory tract), or stomach, as the source dictates the severity and cause.
Oral Health Causes: Minor blood after brushing or flossing often indicates gingivitis or gum disease due to plaque buildup, a common and treatable issue.
Respiratory Infections: Frequent coughing from infections like bronchitis or pneumonia can irritate airways and cause bloody sputum.
Emergency Symptoms: Seek immediate medical care for large amounts of blood, bleeding that won't stop, or accompanying symptoms like chest pain, shortness of breath, or dizziness.
Persistent Bleeding: Even small, persistent amounts of blood over a week warrant a doctor's visit to rule out more serious underlying conditions.
Professional Diagnosis: Only a healthcare provider can accurately diagnose the cause through a physical exam, tests, and potentially imaging to determine the source of the bleeding.

Understanding the Source of the Bleeding

Identifying where the blood is coming from is the most critical part of diagnosing the issue. Blood that is coughed up from the respiratory tract (lungs and throat) is known as hemoptysis, and it often appears mixed with mucus, sometimes frothy or rust-colored. In contrast, blood from the mouth or gums, while also alarming, usually appears with saliva and originates from dental or oral trauma. Finally, blood that is vomited from the stomach, known as hematemesis, is typically dark and may contain traces of food. A doctor will ask you specific questions to help pinpoint the source.

Oral and Dental Causes

One of the most common and least serious reasons for finding blood in your saliva is related to your oral health. Healthy gums do not bleed, so seeing blood after brushing or flossing is often a sign of gingivitis or gum disease.

Gingivitis: This is a mild, reversible form of gum disease caused by plaque buildup that irritates the gums, causing them to bleed and swell.
Aggressive Brushing or Flossing: Using a hard-bristled brush or being too vigorous can cause micro-tears in the delicate gum tissue.
Mouth Sores and Ulcers: Canker sores and other mouth ulcers can bleed when irritated.
Dental Procedures: Minor bleeding after a tooth extraction, deep cleaning, or other dental work is normal.
Teeth Grinding (Bruxism): Nighttime teeth grinding can bruise the gum line and lead to bleeding.

Respiratory System Causes

When blood comes from the lungs or airways, the list of potential causes is more varied and can include infections and other lung conditions.

Respiratory Infections: Acute infections like bronchitis and pneumonia are common causes, as persistent, severe coughing can irritate the respiratory tract and cause bleeding.
Chronic Lung Diseases: Conditions such as chronic obstructive pulmonary disease (COPD), bronchiectasis (permanent widening of airways), and cystic fibrosis can all lead to bloody sputum.
Pulmonary Embolism: This is a serious condition caused by a blood clot in the lung artery, and it often presents with sudden shortness of breath, chest pain, and bloody sputum.
Lung Cancer: Coughing up blood can be an early symptom of lung cancer, particularly in older individuals with a history of smoking.
Tuberculosis (TB): This bacterial infection primarily affects the lungs and can cause fever, night sweats, and a persistent, bloody cough.

Gastrointestinal (GI) System Causes

Though less common than oral or respiratory issues, bleeding from the GI tract can sometimes be mistaken for blood being spit out. This is a serious symptom and requires immediate medical attention.

Peptic Ulcers: Bleeding ulcers in the stomach or intestine can lead to vomiting dark, coffee ground-like blood.
Esophageal Varices: In people with severe liver disease, swollen veins in the esophagus can rupture and cause life-threatening bleeding.

Other Potential Causes

Several other systemic issues or medications can also contribute to the problem.

Anticoagulants: Blood-thinning medications can increase the risk of bleeding in the mouth and respiratory tract.
Heart Conditions: In rare cases, conditions like congestive heart failure can lead to blood-tinged, frothy sputum.
Trauma: A direct injury to the chest or throat can cause internal bleeding that is spit up.

Comparison of Bleeding Sources


Feature	Oral/Dental Bleeding	Respiratory Tract (Hemoptysis)	Gastrointestinal Tract (Hematemesis)
Appearance	Bright red, often mixed directly with saliva.	Pink, frothy, rust-colored, or blood-streaked mucus.	Dark red or brownish, resembling coffee grounds.
Associated Symptoms	Gum pain, inflammation, mouth sores, pain after dental work.	Chronic cough, chest pain, fever, shortness of breath, fatigue.	Nausea, vomiting, abdominal pain, tarry stools.
Taste	Metallic, but primarily a 'blood taste' from the mouth.	Metallic or salty taste.	Acidic or foul taste from stomach contents.
Trigger	Brushing, flossing, eating, or minor oral trauma.	Coughing, respiratory exertion.	Vomiting, abdominal distress.

Diagnosis and Treatment

If you see blood, especially if it persists or is more than a small amount, a healthcare provider will perform a thorough evaluation. This typically starts with a medical history and physical exam. The diagnostic process may include:

Blood Tests: A complete blood count and coagulation tests can check for infections or clotting disorders.
Imaging Tests: A chest X-ray or CT scan can look for tumors, fluid, or other abnormalities in the lungs.
Bronchoscopy: In this procedure, a flexible tube with a camera is passed into the airways to identify the precise location of the bleeding.

Treatment depends on the underlying cause. Mild cases, such as those caused by gum disease, are addressed with improved oral hygiene and dental care. Respiratory infections may be treated with antibiotics or antivirals. More severe conditions like cancer or blood clots may require intensive care, specialized procedures like embolization to stop bleeding, or surgery.

When to Seek Medical Attention

While spitting blood can often have a mild cause, it should not be ignored. It is particularly important to seek medical advice for a proper diagnosis.

Call 911 or seek immediate emergency care if you experience:

Coughing up large amounts of blood (more than a few teaspoons) or if the bleeding won't stop.
Experiencing chest pain, severe shortness of breath, or dizziness alongside the bleeding.
Vomiting blood that appears dark or like coffee grounds.
Blood in your urine or stool.

See a doctor promptly if:

You are spitting up small amounts of blood for more than a week.
The bleeding is accompanied by a fever, night sweats, or unexplained weight loss.

Conclusion

Finding blood in your saliva or sputum is a symptom that demands attention and should not be dismissed. While many causes are minor and easily treatable, such as gum disease or a respiratory infection, others are more serious and require prompt medical intervention. The key to effective treatment lies in accurate diagnosis, which is why consulting a healthcare professional is always the right course of action. By paying close attention to the characteristics of the blood and any accompanying symptoms, you and your doctor can work together to uncover the cause and develop a proper treatment plan. For additional health information, consider reviewing resources from reputable sources like the Cleveland Clinic.

Frequently Asked Questions

A small amount of blood, especially if it only occurs once, may not be serious. However, it is always recommended to see a doctor to ensure there isn't a more serious underlying issue, especially if the bleeding persists for more than a week or is accompanied by other symptoms like fever or chest pain.

The most common reason for spitting blood after brushing is gingivitis, or inflammation of the gums, caused by plaque buildup. Using a brush that is too hard or brushing too aggressively can also cause bleeding.

Coughing up blood (hemoptysis) comes from the lungs or respiratory tract, is often frothy and mixed with mucus, and may appear pink, red, or rust-colored. Vomiting blood (hematemesis) comes from the stomach and is usually dark, resembling coffee grounds.

Yes, a severe or persistent cough from respiratory infections like bronchitis or pneumonia can cause irritation and bleeding in the airways, leading to bloody sputum.

While less common, serious causes include lung conditions like pulmonary embolism (a blood clot in the lung), lung cancer, tuberculosis, or chronic diseases such as cystic fibrosis and COPD.

It is helpful to track and tell your doctor about the amount of blood, its color and consistency (e.g., frothy, mixed with mucus), how long it has been happening, and any other symptoms you are experiencing, such as chest pain, fever, or weight loss.

If you are on blood-thinning medication (anticoagulants), it can increase the risk of bleeding from various sources, including the mouth and respiratory tract. You should inform your doctor about this medication, as it is a crucial piece of information for their diagnosis.