Why Is My Dog Throwing Up Blood? Common Causes and Treatment

If your dog has just vomited and you notice some red in it, you may be wondering why your dog is throwing up blood.  

There are various reasons why your dog may be vomiting blood, ranging from mild issues to more serious health concerns.  

Here you’ll learn what it means when a dog is throwing up blood, including potential causes and what a veterinarian will do to diagnose and treat the underlying condition. 

Why Is My Dog Throwing Up Blood?

Dogs may vomit blood for several reasons.  

Let’s look at the most common causes of a dog vomiting blood. 

Common Causes of Dog Vomiting Blood 

Some possible explanations include: 

• Stomach irritation 
• Stomach ulcers 
• Foreign object ingestion, such as a piece of a bone or toy 
• Toxin exposure, such as rodent bait 
• Severe vomiting causing small tears in the upper digestive tract 
• Clotting disorders, such as hemophilia  
• Certain infections or diseases, such as parvovirus  
• Cancer (less common) 

What Does Blood Thrown Up Look Like?

When a dog is vomiting blood, it can have different appearances depending on which part of the digestive tract is affected.   

You may notice any of the following: 

• Bright red blood (fresh bleeding) 
• Dark brown or black coffee ground–like material (digested blood) 
• Blood mixed with food, foam, or mucus 
• Small streaks versus large amounts of blood 

When Is My Dog Vomiting Blood an Emergency?

If your dog has vomited and there is just a small amount of bright red blood in it, it may mean your dog’s mouth or upper esophagus is irritated.  

In this situation, call your vet for guidance. They will ask you questions and suggest the next steps you should take.  

However, there are a few red flags that would necessitate a call to your veterinarian or an emergency clinic after hours for immediate care, including: 

• Large amounts of blood 
• Repeated vomiting 
• Weakness or collapse 
• Pale gums 
• Trouble breathing 
• Known toxin ingestion 
• Black, tarry stool 
• If your dog is a puppy, senior, or has a chronic illness 

What Will the Veterinarian Do?

If your dog is vomiting blood, your veterinarian will seek to determine the underlying cause using a physical exam, a thorough medical history, and diagnostic testing.  

Let your vet know if your dog may have eaten anything abnormal, such as rodent bait, or if you’ve noticed any other concerning symptoms.  

Be sure to let your vet know if your dog is taking any medications currently.  

Your vet will do a complete head-to-toe exam to check for abnormalities, such as bleeding gums or belly pain.  

To find the underlying reason why your dog is throwing up blood, diagnostic testing may include:  

• Blood work: A small sample of your dog’s blood can be checked for low blood cell counts, clotting abnormalities, or abnormal organ function. 
• Imaging: X-rays and ultrasound can be used to check for foreign objects, masses, and areas of inflammation (swelling) or ulceration (broken tissue). 
• Fecal testing: A sample of your dog’s stool can be checked for parasites or overgrowth of bacteria that can lead to stomach and intestinal irritation and later bleeding. 
• Endoscopy: Your dog is anesthetized, and a small tube is placed inside their mouth to closely look at the esophagus, stomach, and intestines for any abnormalities. Sometimes foreign objects can be removed using this procedure.  

At first, treatment focuses on controlling symptoms and rehydrating your dog. More treatment is dependent on the underlying cause.  

Your vet may recommend any of the following:  

• Intravenous (IV) fluid therapy to support hydration 
• Anti-emetics, such as maropitant, to reduce nausea and vomiting 

• Antacids, such as famotidine, to reduce stomach acid production 

• Antibiotics, such as metronidazole, to treat bacterial infections 

• Surgery to remove foreign objects or masses from the stomach or intestines 
• Coagulation support, such as vitamin K, to stop internal bleeding 

• Activated charcoal to bind toxins to be removed from your dog’s stool  

What Should You Do if Your Dog Is Barfing Up Blood?

If your dog is barfing up blood, first try to remain calm.  

While it is understandably concerning, staying levelheaded can help your dog get the best care.  

Then contact your vet immediately and follow their instructions.  

Your vet may want you to snap a quick photo of the vomit or even grab a small sample to bring in with you. 

Do not give any more food or water by mouth unless the vet has told you to do so.  

Do not give any human medications to your dog in an attempt to stop the vomiting.  

Can a Dog Throwing Up Blood Be Prevented?

Sometimes vomiting blood cannot be prevented, such as if a dog has underlying cancer.  

However, pet parents can take the following proactive steps to keep their dogs safe: 

• Keep toxins and medications securely out of reach of your pet. 
• Prevent foreign object ingestion by supervising your dog with toys and bones. 
• Use medications only as prescribed by your veterinarian. 
• Schedule routine veterinary care to support your dog’s overall health and find concerns early. 
• Seek treatment early for persistent vomiting to find the underlying cause.