Dog Coughing Up Blood and Not Eating: What It Means

Dog Coughing Up Blood and Not Eating: Common Causes 

1. Respiratory Infections (Pneumonia or Bronchitis)

In severe cases of bacterial or viral pneumonia, the lungs become inflamed and fragile. Persistent coughing may lead to capillary damage, causing streaks or flecks of blood in the saliva or phlegm.

You may also notice:

• Lethargy and heavy breathing

• Loss of appetite due to nausea or fatigue

• Fever or chills

• Green or rust-colored mucus

This condition requires immediate veterinary care and antibiotics. Refusal to eat often stems from difficulty breathing or nausea brought on by drainage or the infection itself.

2. Throat or Airway Trauma

Dogs who chew sharp bones, inhale foreign objects, or engage in rough play can injure their throat, windpipe, or esophagus. If these tissues are torn or punctured, they may bleed when the dog coughs or swallows.

Signs include:

• Sudden onset of coughing with blood

• Gagging or trouble swallowing

• Loss of interest in food

• Drooling or pawing at the mouth

Even a small tear can make eating painful, which explains the refusal to eat. An X-ray or endoscopy may be needed to locate the injury or foreign object.

Related: Dog vomiting and not eating (Causes and when to worry)

3. Lung Tumors or Cancer

Cancerous growths in the lungs, throat, or chest can cause coughing and internal bleeding. These tumors may press on airways or blood vessels, eventually causing the dog to cough up blood-streaked mucus or foam.

Look for:

• Chronic coughing that gets worse

• Blood in spit or vomit

• Lethargy and dramatic appetite loss

• Weight loss or muscle wasting

Tumors also increase the risk of internal bleeding and collapse. Appetite may disappear due to pain, nausea, or cancer-related metabolic imbalances. A biopsy or imaging will be required to diagnose cancer.

4. Heartworm Disease

In advanced stages, heartworm disease can damage the lungs and arteries. The worms live in the heart and large blood vessels, and their movement causes scarring and bleeding in the lungs, which may lead to coughing up blood.

Symptoms include:

• Dry, persistent cough

• Fatigue and reduced exercise tolerance

• Loss of appetite and weight loss

• Pale gums or coughing fits with blood

This condition is especially dangerous in unprotected dogs living in mosquito-prone areas. A simple blood test can confirm the diagnosis, and treatment must be carefully managed due to the risk of complications.

5. Ingestion of Poisons or Toxins

Certain toxins—including rat poison (anticoagulants) and household chemicals—can interfere with blood clotting. When this happens, dogs may bleed internally, including into the lungs or digestive tract.

Symptoms to watch for:

• Vomiting blood or coughing blood

• Bruising or bleeding gums

• Weakness, refusal to eat, and collapse

• Black or tarry stools

If ingestion is suspected, treat this as a medical emergency. Time is critical to reverse the effects of poisons before serious damage occurs.

6. Bleeding Disorders (Clotting Abnormalities)

Some dogs are born with or develop clotting disorders, such as Von Willebrand’s disease or thrombocytopenia, which can cause spontaneous bleeding.

These disorders can lead to:

• Bleeding in the lungs or airways

• Coughing up blood, even without injury

• Lethargy and appetite loss due to internal distress

Bleeding disorders often go undetected until triggered by surgery, injury, or illness. Blood tests can determine clotting factor deficiencies and inform treatment plans.

7. Foreign Body Obstruction

Dogs that inhale or swallow foreign objects—like grass awns, splinters, or small toys—can end up with throat or lung trauma. If the object lodges in the airway, it may pierce delicate tissues and cause bleeding when the dog coughs.

You might see:

• Violent coughing fits

• Blood on toys, bedding, or in drool

• Drooling or pawing at the mouth

• Food avoidance due to pain or gag reflex

In these cases, your dog may suddenly stop eating because chewing and swallowing becomes painful. A vet can perform imaging or endoscopy to locate and remove the object safely.

What to Do If Your Dog Is Coughing Up Blood and Not Eating

This situation is rarely one to “wait and see.” However, if symptoms are mild and your dog is stable, take these steps while preparing for a vet visit:

• Keep your dog calm and limit activity to avoid triggering more coughing

• Offer water or ice chips to keep them hydrated without overexerting the throat

• Avoid hard or dry foods—try soft, bland meals like boiled chicken and rice

• Check the gums—if pale or bright red, it may indicate blood loss or poor oxygenation

• Note the color and volume of blood to share with your vet

But if your dog continues coughing up blood, refuses all food, or seems lethargic, seek emergency care.

When to Call or Visit Your Vet

Call or visit your vet immediately if your dog:

• Coughs up bright red blood or blood-streaked mucus

• Refuses food for more than 24 hours

• Shows signs of difficulty breathing or blue gums

• Vomits blood or has black/tarry stools

• Collapses, is unresponsive, or breathing heavily

These symptoms suggest internal bleeding, respiratory failure, or another life-threatening issue that needs urgent care.

Your vet may perform imaging (like X-rays), blood work, clotting panels, or endoscopy to determine the cause.

• Related: Dog cold and not eating (What it means)

Key Takeaway

If your dog is coughing up blood and not eating, don’t ignore the signs.

These symptoms often signal something serious—from infection and trauma to cancer or toxin ingestion.

Getting to the root of the issue quickly could save your dog’s life.

Trust your instincts and don’t delay seeking care. Even if it turns out to be minor, you’ll have peace of mind—and your dog will feel better faster with the right support and treatment.