Why Is My Dog Throwing Up Black or Dark Brown Vomit?

If dog vomit is brown, several underlying causes could be to blame, including:

Dietary Indiscretion

Brown—either darker or lighter shades—is likely the most common color of dog vomit because most dog food is brown, says Dr. Monica Sterk, DVM, regional medical director at Veterinary Emergency Group, which has locations in over 65 US cities.

If your dog has recently eaten dark brown-colored kibble or treats and then vomits, the color of the food could be the reason for the vomit’s dark brown shade. In such instances, the vomiting might result from a range of causes, such as an upset stomach due to eating too fast, gastroenteritis or an intestinal blockage.

If your dog ingests human foods that are brown, such as chocolate (which is toxic to dogs), or nonfood items like dirt or feces, their vomit might also appear dark brown. In some cases, you can tell what your dog consumed based on the smell of the vomit.

Internal Bleeding

One red flag is if dark brown vomit resembles coffee grounds, as this is usually a sign of bleeding in the gastrointestinal tract, Dr. Sterk says.

Common reasons for internal bleeding include:

• Stomach ulcers
• Ingestion of toxins, such as certain plants, rat poison, cleaning products and other household items
• Ingestion of a foreign body, such as a toy or a piece of glass
• An internal abdominal injury
• Coagulation (blood clotting) disorders
• Intestinal parasites
• Colitis or inflammatory bowel disease (IBD)
• Benign or malignant tumors

Liver Disease

A dog throwing up brown liquid could signal liver disease.

“Liver disease can lead to vomiting brown liquid due to blood from the digestive tract mixing with stomach acid,” says Dr. Bethany Hsia, DVM, co-founder of CodaPet, which has locations in over 10 US cities.

Black dog vomit can indicate the presence of digested blood, says Dr. Andrea Johnston, DVM, board-certified small animal veterinary internist and medical board member at The Vets, a national mobile pet care service.

Blood, when digested, turns black and generally suggests internal bleeding, the potential causes of which include stomach ulcers, intestinal parasites and abdominal bleeding.

“Ingestion of substances like certain medications, iron supplements or activated charcoal can also cause black stools and vomit,” says Dr. Johnston.

Red vomit often rings alarm bells for pet parents—and rightly so. This may suggest the presence of fresh blood, indicating bleeding possibly in the stomach or upper small intestine. The causes of internal bleeding in this area could be intestinal ulcers; ingestion of a foreign object; an internal injury; or any of the other causes listed above.

Red vomit can also mean your dog ate something red, such as watermelon, beets or foods with red food coloring, or that there’s a bleeding wound in their mouth, throat or esophagus, says Dr. Hsia.

What Are Stomach Ulcers?

Stomach ulcers are painful, open sores that develop on the inner lining of a dog’s stomach. They are also one of the most common causes of intestinal bleeding, Dr. Hsia says.

The discomfort of ulcers can affect your dog’s appetite and behavior, leading to weight loss, lethargy and a noticeable decrease in general activity levels. If left untreated, stomach ulcers can lead to bleeding in the gastrointestinal tract, evident in symptoms like red, black or dark brown vomit, or passing dark, tarry stools.

In severe cases, a stomach ulcer can perforate, meaning it creates a hole in the stomach wall. This serious condition can lead to peritonitis, an infection of the abdominal cavity, which is a life-threatening medical emergency requiring immediate surgical intervention.

What Causes Stomach Ulcers?

Digestive enzymes work to break down food in the digestive tract. The inner lining of the digestive tract serves as a shield, guarding the tissues against the corrosive nature of stomach acid, Dr. Hsia says.

When this protective lining is compromised, or when there’s excessive production of acid that overwhelms the lining’s protective capacity, it leads to the erosion of this barrier. This erosion results in sores or ulcers within the stomach wall.

Stomach ulcers can develop over time as a result of:

• Prolonged use or high doses of nonsteroidal anti-inflammatory drugs (NSAIDs)
• Gastrointestinal diseases, such as inflammatory bowel disease or gastritis
• Infectious diseases, such as pythiosis and Helicobacter pylori infections
• Diseases involving the liver, kidneys or adrenal glands
• Ingestion of poison, toxins or heavy metals
• Cancers of the gastrointestinal tract
• Stress, which can include things like severe shock or frequent strenuous exercise (as seen with elite canine athletes and sled dogs)

How to Prevent Stomach Ulcers

While it's next to impossible to guarantee the complete prevention of stomach ulcers in dogs due to the variety of contributing factors, implementing certain proactive measures can significantly reduce the risk.

• Careful use of medications: Always use NSAIDs and other medications as prescribed by your veterinarian. If your dog needs long-term medication, consult with your vet about potential stomach-protective measures.
• Balanced diet: Feed your dog a balanced diet appropriate for their age, size and health status. Avoid sudden dietary changes, and resist the urge to give them lots of human food as treats, as this could irritate their stomach. Your vet can recommend an appropriate diet for your dog.
• Keeping toxins out of reach: Keep potential toxins, including certain plants, human medications and household cleaners, out of your dog's reach.
• Regular veterinary checkups: Regular checkups can help identify and manage underlying health conditions that might lead to ulcers.
• Awareness of physical health: Keep an eye on your dog’s health. Any signs of discomfort, changes in eating habits or symptoms like vomiting should be checked by a vet.

When is it necessary to take your vomiting pup to the vet? And when is it OK to take a wait-and-see approach? Dr. Johnston shares some guidelines:

• Vomiting frequency, duration and severity: If your dog vomits once or twice and then seems fine, it’s likely not a cause for concern. However, if vomiting is frequent, continuous, violent or lasts more than 24 hours, it’s time to visit your vet.
• Presence of other symptoms: Watch for other signs of illness, such as lethargy, diarrhea, abdominal pain, stomach bloat, changes in behavior or refusal to eat. If your dog shows multiple symptoms, head to the vet promptly.
• Age of the dog: Puppies and elderly dogs can quickly become dehydrated due to vomiting. Any signs of dehydration should be swiftly addressed with a vet.
• Appearance of the vomit: If your dog’s vomit is black, red or looks like coffee grounds, seek prompt veterinary care, as these could be signs of internal bleeding.
• Foreign objects or toxins: If you suspect your dog has ingested a foreign object, toxic substance or human food harmful to dogs, seek emergency veterinary care.

Remember, it’s better to be overly cautious than miss a serious health issue, Dr. Johnston says.

Black or dark brown vomit dog treatment varies depending on the underlying causes, which are determined through various diagnostic tests, such as blood work and imaging, says Dr. Johnston. However, there are general approaches, including:

• Medications: Depending on the cause, various medications may be prescribed, such as those to control vomiting; soothe and protect the stomach lining; reduce stomach acid; or treat an infection.
• Diet change: In cases where dietary indiscretion is a factor, withholding food for one meal might be warranted to give the digestive system a rest, says Dr. Johnston. From there, you can gradually reintroduce a bland diet, such as boiled chicken and rice, for a few days before resuming their regular diet or switching to a new one, she adds.
• Fluid therapy: If your dog is dehydrated, intravenous or subcutaneous fluid therapy may be necessary to restore hydration and electrolyte balance.
• Treating underlying conditions: If the black, dark brown or red vomit is a symptom of a more serious condition, such as a tumor or ingestion of a foreign body, specific treatments targeting these issues will be necessary. This may include medication, fluids, special diets and surgery.

Your vet will determine the best treatment for your dog.