Seeing your dog have loose stool and vomit white foam can be frightening and confusing.
These symptoms often signal irritation or inflammation in the stomach and intestines, and they can range from mild digestive upset to signs of something more serious.
We outline the common reasons why a dog may have loose stool and vomit white foam, what you can do at home, and when to seek veterinary help.
Dog Has Loose Stool and Throwing Up White Foam: Why It Happens
When a dog vomits white foam and also has loose stool, it usually means their digestive tract is inflamed or reacting to something it can’t process properly. The foam itself often forms when stomach acid and saliva mix during repeated vomiting, while loose stool indicates the intestines are trying to flush something out.
Although mild cases can sometimes resolve with rest and hydration, it’s essential to pay attention to how long it lasts and how your dog behaves overall.
Dog Has Loose Stool and Throwing Up White Foam: Common Causes
Dietary Indiscretion
One of the most frequent reasons dogs have loose stool and vomit white foam is dietary indiscretion — in other words, eating something they shouldn’t.
Dogs are notorious scavengers and can easily find spoiled food, garbage, or even foreign objects during walks or play.
When a dog ingests spoiled or fatty food, the stomach becomes irritated and starts to produce excess acid. This can cause the white foamy vomit you see, while the intestines respond with diarrhea to eliminate the irritant.
Owners often report sudden symptoms after a trip to the park, rummaging through the trash, or being fed table scraps.
Most mild cases resolve within 24 hours if the stomach is given time to settle, but continued vomiting or worsening diarrhea can signal a more serious reaction that needs medical attention.
Read more: Dog Loose Stool with No Other Symptoms (What it means)
Gastritis (Stomach Inflammation)
Gastritis occurs when your dog’s stomach lining becomes inflamed, often due to overeating, stress, or ingestion of harmful substances. This irritation causes nausea, frequent swallowing, drooling, vomiting of white or yellowish foam, and loose stool.
Because gastritis affects the stomach directly, dogs may appear restless, stretch frequently, or lick their lips excessively before vomiting. The condition can be acute — appearing suddenly — or chronic if underlying issues like poor diet, food allergies, or infections are involved.
Persistent gastritis requires veterinary care since dehydration and loss of electrolytes can happen quickly, especially if diarrhea and vomiting occur together.
Intestinal Parasites
Parasites like roundworms, whipworms, and giardia can disrupt the digestive process and cause both loose stool and vomiting. Infected dogs may have soft or watery stool, sometimes with mucus or a foul odor, and may vomit white foam if the stomach becomes irritated.
These parasites damage the intestinal lining, preventing normal absorption of nutrients and leading to inflammation and excess gas. Puppies, in particular, are highly vulnerable because their immune systems are still developing.
Left untreated, parasitic infections can lead to anemia, weight loss, and chronic digestive issues. Routine deworming and fecal checks are the best ways to prevent this issue and maintain gut health.
Read more: Dog Loose Stool and Vomiting Bile (How to tell if it’s serious)
Pancreatitis
Pancreatitis — inflammation of the pancreas — is another common cause of loose stool and vomiting white foam in dogs. It often occurs after eating rich, fatty meals or human foods like bacon, gravy, or butter.
The pancreas releases digestive enzymes prematurely, which then begin to attack the organ itself, causing pain and inflammation.
Dogs with pancreatitis may show signs of severe abdominal discomfort, hunched posture, loss of appetite, and fatigue. The vomit is frequently foamy or yellowish, while the stool becomes loose and greasy due to poor fat digestion.
This condition is serious and can become life-threatening if not treated promptly. Veterinary care typically involves fasting, IV fluids, and medication to reduce inflammation and pain.
Gastroenteritis
Gastroenteritis is a general term for inflammation of the stomach and intestines, usually caused by bacteria, viruses, or something your dog ingested. The combination of vomiting foam and loose stool fits this pattern perfectly.
Dogs with gastroenteritis often appear lethargic, have reduced appetite, and may vomit repeatedly.
The white foam results from irritation of the stomach lining, while the loose stool indicates inflammation further down the digestive tract.
Although many cases are mild, persistent vomiting or diarrhea can quickly lead to dehydration. In more severe cases, your vet may prescribe fluids, anti-nausea medication, or antibiotics depending on the underlying cause.
Bloat (Gastric Dilatation and Volvulus)
Though less common, bloat is a medical emergency that can cause vomiting of white foam along with discomfort and unsuccessful attempts to defecate. Large, deep-chested breeds such as Great Danes, German Shepherds, and Boxers are at higher risk.
During bloat, the stomach fills with gas and twists, trapping contents inside. The pressure prevents normal digestion and can lead to rapid deterioration if not treated immediately.
Dogs with bloat often retch without producing much except white foam, show signs of distress, and may have a swollen abdomen.
If you suspect bloat, seek emergency veterinary care right away — minutes can make the difference between life and death.
Read more: Dog Loose Stool and Vomiting (Why it happens and when to worry)
What to Do If Your Dog Has Loose Stool and Throwing Up White Foam
Start by withholding food for about 12 hours to allow your dog’s digestive system to rest, but always provide access to fresh, clean water to prevent dehydration.
After the fasting period, offer small portions of a bland diet — boiled chicken and rice or a prescription gastrointestinal diet — to help soothe the stomach.
Monitor your dog closely over the next 24–48 hours. If the vomiting and diarrhea improve, you can gradually reintroduce their normal food. Avoid giving treats, table scraps, or fatty foods during recovery, as they can easily trigger symptoms again.
If your dog seems tired, refuses water, or continues vomiting, it’s important not to delay veterinary care. Persistent vomiting and diarrhea can cause electrolyte imbalances and dehydration, which require professional treatment.
You can also collect a stool sample to bring to the vet for parasite testing, which speeds up diagnosis.
When to Call or Visit Your Vet
You should contact your veterinarian immediately if your dog’s vomiting and loose stool last more than 24 hours or are accompanied by blood, weakness, or signs of dehydration such as dry gums or sunken eyes.
Persistent vomiting of white foam can also indicate a blockage, pancreatitis, or bloat, all of which are emergencies.
If your dog is lethargic, refuses food or water, or has a bloated or painful abdomen, do not wait — these are signs of a potentially life-threatening problem.
Puppies, senior dogs, and those with preexisting conditions like diabetes or kidney disease are more vulnerable and should be examined promptly.
During your visit, your vet may perform diagnostic tests such as bloodwork, X-rays, or ultrasound to identify the cause and tailor treatment. Early intervention can prevent serious complications and help your dog recover faster.
Read more: Dog Loose Stool (What it means)
Key Takeaway
When your dog has loose stool and throws up white foam, it’s a sign that their digestive system is struggling — whether from something they ate, an infection, or a more serious internal issue.
While mild cases can resolve with rest, hydration, and a gentle diet, prolonged or worsening symptoms require veterinary care.
Stay calm, keep your dog comfortable, and avoid home remedies that could make things worse.
Acting promptly and compassionately ensures your dog gets the right care, whether it’s a simple stomach upset or a sign of something more complex. Your attentiveness can make all the difference in their recovery and well-being.