Dog Vomiting White Foamy Mucus and Blood (What It Means)

Dog Vomiting White Foamy Mucus and Blood: Common Causes

Gastritis 

Gastritis occurs when the stomach lining becomes inflamed from irritation, stress, spoiled food, sudden diet changes, or ingestion of something toxic or indigestible.

When the stomach is irritated, it releases excess acid and mucus, which creates the white foamy texture.

Repeated vomiting irritates the lining even more, eventually causing small blood vessels to tear, resulting in streaks of bright red blood mixed with the foam.

A dog with gastritis may vomit multiple times in a row, retch without producing food, or have a gurgling stomach. The mixture of foamy mucus and fresh blood indicates the stomach is struggling.

Because the irritation intensifies with every vomit, the blood often appears after several episodes.

Dogs may pace, lick their lips, or refuse food due to nausea. Gastritis can be mild or severe, but vomiting blood always elevates the concern.

Read more: Dog coughing up white foamy mucus (What it means)

Ulcers in the Stomach or Upper Intestine

Stomach ulcers allow acid to erode the stomach lining, causing pain, nausea, and vomiting that often includes white foam mixed with blood.

Dogs develop ulcers from medications such as NSAIDs (pain relievers), long-term steroid use, infections, kidney disease, or chronic stress.

When an ulcer bleeds, the dog may vomit bright red streaks or small clots of blood. The foamy mucus appears because the irritated stomach produces excess secretions during vomiting.

Dogs with ulcers often show signs of abdominal discomfort, loss of appetite, weight loss, or dark stool.

Ulcers worsen rapidly if untreated, and vomiting foam with blood is a classic warning sign.

Foreign Body Ingestion

If a dog swallows something that becomes stuck—such as a toy, bone fragment, sock, corn cob, or piece of fabric—the stomach reacts violently.

The dog may attempt to vomit repeatedly, but because the obstruction prevents contents from passing normally, they often produce only white foam, mucus, and eventually blood from the strain.

Foreign bodies scrape and irritate the esophagus or stomach lining during retching, which introduces blood into the vomit.

Signs often escalate quickly: pacing, drooling, swollen abdomen, and repeated attempts to vomit with nothing coming up except foam.

This is one of the most dangerous causes and can turn life-threatening within hours.

Pancreatitis

Pancreatitis occurs when the pancreas becomes inflamed and begins releasing enzymes that damage surrounding tissues.

Dogs with pancreatitis often vomit repeatedly, producing white or yellow foam. As the irritation continues, blood may appear from damage to the stomach lining.

Pancreatitis can cause severe abdominal pain, hunched posture, lethargy, shaking, and refusal to eat.

Vomiting becomes more violent and frequent as inflammation worsens, and blood may appear when the stomach becomes raw and inflamed.
Pancreatitis is often triggered by rich or fatty foods, toxins, or metabolic issues.

This condition requires immediate veterinary attention because it can progress rapidly and painfully.

Hemorrhagic Gastroenteritis (HGE)

HGE causes sudden, severe inflammation in the digestive tract and can produce vomiting that includes mucus, foam, and bright red blood.
Dogs with HGE often vomit forcefully and repeatedly, which quickly irritates the lining and results in blood appearing in the foam.

The illness also typically causes bloody diarrhea, dehydration, and lethargy. Small breeds are especially vulnerable, but all dogs can develop HGE.
Because blood loss and dehydration happen quickly, HGE is considered a medical emergency.

Acid Reflux and Esophagus Irritation

If a dog experiences severe reflux or vomits repeatedly, acid can burn the esophagus. When the tissues become inflamed, the dog may vomit white foamy mucus containing blood because the esophagus is raw or bleeding.

Reflux-related vomiting often happens when the stomach is empty, such as early morning or late at night. Dogs may swallow repeatedly, cough lightly, or show throat discomfort.

Though reflux alone rarely causes significant blood, repeated irritation can introduce streaks of red into the foam.

Toxin Ingestion

Certain toxins—such as rat poison, medications, toxic plants, cleaners, or spoiled food—can cause repeated vomiting that leads to foamy mucus and internal bleeding.

Some toxins act directly on the stomach lining, while others cause bleeding disorders that make even minor irritation produce visible blood.

Dogs may show sudden vomiting, drooling, tremors, pale gums, or collapse depending on the toxin.

Whenever vomiting contains blood and a toxin is suspected, emergency care is critical.

Severe Gastrointestinal Infection 

Parvovirus, bacterial infections, and severe parasitic infections can all cause a dog to vomit foam mixed with blood. These illnesses inflame the digestive tract so severely that the stomach bleeds as vomiting continues.

Parvo is especially dangerous and often begins with white foam that progresses to blood as the stomach lining deteriorates. Dogs may become lethargic, dehydrated, and depressed quickly.

Read more: Dog Vomiting Blood and Pooping Blood (Why both symptoms are dangerous)

What to Do If Your Dog Is Vomiting White Foamy Mucus and Blood

Begin by keeping your dog calm and withholding food for a short period to rest the stomach. Do not offer rich foods, treats, or random home remedies. Provide small sips of water or ice cubes to help prevent dehydration, but avoid letting your dog gulp water quickly as it can cause more vomiting.

Observe how often the vomiting occurs and whether additional symptoms appear. Check the vomit for objects, foreign material, or unusual colors that may indicate ingestion of something harmful.

Prevent your dog from eating grass, chewing toys, or accessing any potential toxins until the vomiting stops. If there is any chance your dog swallowed something or was exposed to poisons, assume the situation is serious.

Do not give human medications—many worsen bleeding or increase stomach irritation. Do not wait more than a few hours for improvement; blood in vomit means the digestive tract is injured or inflamed.

Even if your dog seems alert between episodes, vomiting foam with blood always warrants veterinary evaluation.

When to Call or Visit Your Vet

Contact your veterinarian immediately if your dog:

• Vomits white foam mixed with any amount of blood.
• Vomits repeatedly or cannot keep water down.
• Shows lethargy, shaking, or weakness.
• Has a swollen or painful abdomen.
• Has eaten something inappropriate or possibly toxic.
• Has black stool or blood in stool.
• Appears dehydrated (dry gums, sunken eyes, weakness).
• Has pale, white, or gray gums.
• Shows signs of abdominal pain or distress.
• Refuses food or water after vomiting.
• Has diarrhea along with vomiting blood.

Seek emergency care if:

• Your dog vomits blood more than once.
• Blood appears suddenly and in large amounts.
• Vomiting is accompanied by collapse.
• A foreign object ingestion is likely.
• Your dog is a puppy, senior, or has underlying medical conditions.

Bloody vomiting can escalate rapidly and must never be monitored at home without veterinary input.

Read more: Dog Vomiting Undigested Food Hours Later (Here’s why)

Key Takeaway

When a dog vomits white foamy mucus and blood, the stomach or esophagus is significantly irritated or injured.

This combination of symptoms can signal ulcers, pancreatitis, toxins, infection, or obstruction—and requires urgent veterinary attention.

With quick care, supportive treatment, and addressing the underlying cause, most dogs recover safely and comfortably.