Dogs coughing up blood and mucus is one of the most alarming symptoms a pet owner can witness.
It often signals irritation, or bleeding somewhere in the respiratory system, and in some cases, it may indicate a serious underlying condition.
We outline the common causes of a dog coughing up blood and mucus, what you can do at home, and when to seek veterinary help.
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Dog Coughing Up Blood and Mucus — Why It Happens
A dog coughing up blood and mucus usually means the airways, throat, or lungs are inflamed, damaged, or infected. Blood can appear in the mucus when fragile respiratory tissues become irritated from a severe cough, infection, trauma, or a more serious disease.
This symptom may occur with pneumonia, kennel cough complications, foreign body irritation, lung tumors, or bleeding disorders.
Some dogs also cough up blood due to trauma from pulling on a collar or from inhaling debris. Because blood in mucus signals tissue injury, it’s important to treat this symptom promptly.
Dog Coughing Up Blood and Mucus: Common Causes
Severe Kennel Cough or Respiratory Infection
Severe cases of kennel cough can lead to intense, repetitive coughing that irritates the throat and upper airways.
As the tissues become inflamed, tiny blood vessels may rupture, causing streaks of blood in the mucus.
Dogs may experience gagging, hacking, retching, or coughing fits that end in bloody phlegm.
Although mild kennel cough usually improves on its own, severe or persistent cases can progress into pneumonia and require veterinary treatment.
Read more: Dog coughing up white foamy mucus (Here’s why)
Pneumonia
Pneumonia causes deep inflammation in the lungs, resulting in coughing that may produce thick mucus tinged with blood.
Affected dogs often have labored breathing, fever, loss of appetite, weakness, or lethargy.
The blood appears when the lungs struggle to manage inflammation and excess fluid.
Because pneumonia compromises oxygen exchange, it is considered a medical emergency and requires urgent treatment.
Foreign Body in the Airway
Dogs sometimes inhale grass awns, dirt, small sticks, or other debris, which can scratch or puncture respiratory tissues.
This irritation can lead to coughing up blood and mucus as the body attempts to expel the object.
Dogs may paw at their face, swallow repeatedly, or show sudden distress.
Foreign material in the airway is extremely serious because it can block breathing or cause infection.
Lung Tumors or Cancer
Lung tumors—whether primary or spread from another part of the body—can cause dogs to cough up blood and mucus.
Coughing tends to be persistent, sometimes worsening over weeks or months.
Weight loss, fatigue, exercise intolerance, and breathing changes may also appear.
Because tumors disrupt lung tissue, even mild coughing can result in bleeding.
Bleeding Disorders
Some dogs have clotting disorders that make them more prone to bleeding, even from minor irritation.
Conditions like rodenticide poisoning, immune-mediated thrombocytopenia (IMT), or congenital clotting defects can cause blood to appear in mucus.
These dogs may also bruise easily or have bleeding in other areas such as the gums or nose.
This is a medical emergency that requires immediate intervention.
Severe Throat or Tracheal Irritation
Dogs who pull hard on the leash, cough excessively, or have tracheal collapse may irritate the lining of the throat.
This can lead to minor bleeding mixed with mucus during coughing fits.
Small-breed dogs are especially vulnerable.
While irritation alone is not usually dangerous, ongoing bleeding must be evaluated by a veterinarian.
Read more: Dog Coughing with No Other Symptoms (What it means)
What to Do If Your Dog Is Coughing Up Blood and Mucus
If your dog is coughing up blood and mucus, keep them calm and restrict activity. Excitement and movement can trigger harder coughing, which may worsen irritation and bleeding.
Make sure your dog has access to fresh water, as hydration helps thin mucus and makes coughing less painful.
Use a harness instead of a collar to avoid putting pressure on the throat during walks. Even gentle pulling can aggravate bleeding in an already irritated airway.
If you suspect your dog inhaled something while outdoors, avoid offering food until a veterinarian examines them. Some foreign objects can shift during swallowing.
Dogs showing signs of respiratory infection may benefit from a humidifier or sitting in a steamy bathroom to soothe the airways.
Because coughing up blood is never considered a mild symptom, monitor your dog closely and prepare for a prompt veterinary visit.
When to Call or Visit Your Vet
Call your veterinarian immediately if your dog is coughing up blood and mucus, even if the amount of blood seems small.
Seek urgent care if your dog is also experiencing trouble breathing, wheezing, or rapid, shallow breaths.
A dog who becomes lethargic, weak, or refuses food needs prompt medical attention.
If there is a chance of foreign body inhalation, rodenticide exposure, or trauma, emergency care is essential.
Persistent coughing for more than 24 hours, worsening bleeding, pale gums, or collapse are red flags that require immediate hospitalization.
Read more: Dog Throwing Up and Coughing (Why it happens)
Key Takeaway
A dog coughing up blood and mucus is always a concerning symptom that warrants close attention and timely veterinary care. While some causes are mild and treatable, others can be life-threatening without quick intervention.
Stay calm, minimize coughing triggers, and seek help promptly to protect your dog’s health and comfort.