Gastritis in Dogs: Symptoms, Causes and Red Flags

Gastritis in dogs is inflammation of the stomach lining, and the most common cause is the simplest one: your dog ate something the stomach objected to. Garbage, spoiled food, a stolen fatty meal, mulch, a mouthful of grass, a chewed-up piece of a toy. Beyond that — what vets call dietary indiscretion — the usual triggers are medications that irritate the mucosa (NSAIDs and corticosteroids in particular), bacterial or viral infection, intestinal parasites, swallowed foreign material, toxic plants or household chemicals, food intolerance and allergy, and, in longer-running cases, disease somewhere else in the body: kidney disease, liver disease, pancreatitis, Addison's disease or inflammatory bowel disease. Chronic stress belongs on that list too.

The stomach lining is a working barrier. A mucus layer, a tight sheet of epithelial cells and a steady blood supply keep stomach acid where it belongs. Anything that thins the mucus, damages the cells or reduces blood flow to that lining leaves acid in contact with tissue that was never built to tolerate it — and the result is the vomiting, nausea and appetite loss owners come looking for answers about.

The signs owners notice first

Most owners do not arrive at the word gastritis. They arrive at "my dog keeps throwing up and won't eat." Here is what that looks like in detail:

• Vomiting. The hallmark sign. It may be undigested food shortly after a meal, white foam, or yellow-green bile on an empty stomach — bile vomiting often happens in the early morning hours.
• Nausea cues before the vomit. Repeated lip-licking, drooling, hard swallowing, pacing, restlessness, standing with the head low. Many dogs show these for a while before anything comes up.
• Loss of appetite. Turning away from food, eating half a meal, or taking a treat and then dropping it.
• Grass eating. Common in dogs with an still developing stomach, though it is a symptom rather than a cause.
• Lethargy and withdrawal. Sleeping more, less interested in walks, less responsive to the usual triggers.
• Abdominal discomfort. A hunched posture, a tense belly, the "prayer position" with chest down and rear up, flinching when lifted, or reluctance to be picked up at all.
• Audible gut sounds. Loud gurgling (borborygmi) is frequently reported alongside nausea.
• Dehydration. Tacky or dry gums, skin that is slow to flatten when gently tented, sunken-looking eyes.
• Blood. Fresh red streaks in vomit, or material that looks like coffee grounds — that is digested blood. Black, tarry stool (melena) means blood has passed through the digestive tract.
• Weight loss and a dull coat. These tend to show up when the problem has been running for weeks rather than days.

One episode of vomiting in an otherwise bright, hungry dog is usually not the same conversation as a dog who has vomited six times overnight, refused breakfast and is lying in a different room than usual. Severity, frequency and the dog's overall demeanour matter more than any single symptom on the list.

Acute or chronic: two different patterns

Vets broadly split stomach-lining inflammation into sudden-onset and long-running forms, and they rarely come from the same place.

	Acute	Chronic
Onset	Sudden, often traceable to a specific event	Gradual, waxing and waning over weeks or months
Typical presentation	Repeated vomiting, appetite loss, lethargy	Intermittent vomiting, picky eating, slow weight loss, dull coat
Common triggers	Garbage, spoiled food, toxin, foreign body, medication reaction, infection	Food intolerance, inflammatory bowel disease, parasites, kidney or liver disease, long-term medication, ongoing stress
At home it looks like	A dog who was fine yesterday and is clearly unwell today	A dog who "has a sensitive stomach" and throws up most weeks
Veterinary urgency	Same-day if vomiting is repeated, bloody or paired with pain	Needs a workup — recurring vomiting is never normal

The chronic column is the one owners most often normalise. A dog who vomits bile every few mornings is telling you something about his stomach lining, not displaying a personality quirk.

The triggers behind an inflamed stomach lining

Dietary indiscretion. The single biggest cause. Bin raids, counter surfing, rich table scraps, rotten material found on a walk, abrupt diet changes, or food that simply doesn't suit the individual dog.

Foreign material. Socks, bone fragments, corn cobs, sticks, rocks, fabric. These both irritate the lining directly and can obstruct the gut, which is a surgical emergency.

Medications. Non-steroidal anti-inflammatories and corticosteroids can irritate the gastric mucosa, which is exactly why they are prescribed at a considered dose and often with food or a gastroprotectant. If you suspect a prescription is upsetting your dog's stomach, call the prescribing vet — never simply stop a medication your dog has been put on.

Infection and parasites. Bacterial and viral infections, Helicobacter species, roundworms, hookworms, whipworms and Giardia can all inflame the digestive tract.

Toxins. Household cleaners, antifreeze, xylitol, chocolate, grapes, certain plants, fertilisers and some human medications. Suspected toxin exposure is an immediate call, not a wait-and-see.

Food intolerance and allergy. A protein or ingredient the immune system reacts to can keep the gut in a low-grade inflammatory state indefinitely.

Systemic disease. Kidney disease, liver disease, pancreatitis, Addison's disease, inflammatory bowel disease and, in older dogs, gastric tumours can all present as stomach inflammation. This is why recurring vomiting earns bloodwork rather than another bland-diet weekend.

Can stress set off a dog's stomach?

Yes — stress is a recognised contributor to gastrointestinal upset in dogs, and it works through real physiology rather than sympathy. The gut and the brain communicate constantly through the vagus nerve and a cascade of stress hormones. Sustained stress shifts gut motility, alters blood flow to the digestive tract and affects the mucus and bicarbonate layer that shields the stomach lining from its own acid. Veterinary medicine has long described stress-related colitis for the same reason.

The practical triggers are familiar: boarding kennels, a house move, a new baby or new pet, building work, fireworks, separation anxiety, long travel, or the disrupted routine that follows an injury or surgery. Stress is rarely the whole story on its own — more often it lowers the threshold, so a dog under pressure reacts to a dietary slip that he would have shrugged off in a calm month.

If your dog's vomiting tracks reliably with specific events, that pattern is genuinely useful information. Write it down and bring it to your veterinarian, because behavioural management and medical management are not mutually exclusive.

Red flags, and what your veterinarian will actually do

Vomiting that continues past a day, contains blood, or arrives alongside a tense and painful abdomen is not a wait-and-see situation — call your veterinarian. The same goes for black tarry stool, pale gums, collapse, known toxin exposure, a hard distended belly with unproductive retching (a possible gastric dilatation-volvulus, which is immediately life-threatening), and any vomiting at all in a young puppy, a senior dog or a dog with an existing medical condition. Small dogs and puppies dehydrate quickly.

A workup typically starts with history and abdominal palpation, then moves through bloodwork and urinalysis, a faecal test for parasites, and imaging — radiographs or ultrasound — to look for foreign material, obstruction or organ changes. Persistent cases may go to endoscopy with biopsy, which is the only way to see the stomach lining directly and characterise the inflammation.

Supportive care is directed by the findings: fluids for dehydration, anti-nausea medication, gastroprotectants, a short rest-and-reintroduce feeding plan, deworming, a diet trial, or treatment aimed at whichever underlying disease turned up. That plan belongs to your vet, and following it properly is the most useful thing an owner can do.

Where peptides fit into a recovery conversation

Owners researching gut inflammation often land on peptides, so it is worth being precise. K9-REPAIR is pawgen's BPC-157 and TB-500 formulation for dogs, and it is formulated around joint, tendon and mobility recovery — the slow, structural repair work that follows a cruciate injury, a soft-tissue strain or an orthopaedic procedure. It is not a treatment for gastritis, and a dog who is actively vomiting needs a diagnosis from a veterinarian, not a new supplement.

What makes the chemistry interesting to owners is its origin. BPC-157 stands for Body Protection Compound — it is a synthetic peptide sequence based on a protein identified in gastric juice, and the published laboratory work on it has focused heavily on tissue repair processes, including angiogenesis and cell migration. TB-500 is related to thymosin beta-4, a naturally occurring peptide involved in actin regulation and cell movement during healing. Research in animal models suggests these peptides may support the body's own repair signalling; this is emerging science that owners are increasingly adopting through recovery periods, and it is not FDA-approved veterinary medicine.

What pawgen can state plainly is what is in the bottle. K9-REPAIR is a defined two-peptide formulation rather than a kitchen-sink chew with a proprietary blend hiding token amounts of a dozen ingredients. Dosing is weight-based and should be worked out with your veterinarian, batches are third-party tested with certificates of analysis published, it ships direct to the door, and it is backed by a 60-day money-back guarantee.

Key Takeaways

• Gastritis is inflammation of the stomach lining; dietary indiscretion is the most common trigger, followed by medications, infection, parasites, foreign material, toxins, food intolerance and underlying systemic disease.
• The signs to watch are vomiting (food, foam or bile), lip-licking and drooling, appetite loss, lethargy, grass eating, a hunched or tense abdomen and loud gut sounds.
• Blood in vomit, black tarry stool, pale gums, a hard distended belly with unproductive retching, or vomiting in a puppy or senior dog all warrant an urgent call.
• Stress is a genuine contributor through gut-brain signalling, motility changes and reduced mucosal protection — keep a note of which events coincide with flare-ups.
• Recurring vomiting is never a personality trait. It deserves bloodwork, a faecal test and imaging.
• K9-REPAIR is built for joint, tendon and mobility recovery and is not a treatment for stomach conditions; talk to your veterinarian before adding anything to an unwell dog's routine.

Your veterinarian owns the diagnosis and the treatment plan — the bloodwork, the imaging, the prescriptions, the feeding protocol and the decision about what is actually driving the inflammation. Supplements and peptides operate only in the space that proper veterinary care creates, and they operate best when your vet knows exactly what your dog is receiving.

If you want to look further at pawgen's approach, batch certificates of analysis are published at /coas/, the current K9-REPAIR lineup sits at /shop/, and shipping destinations are listed at /location/.

Owners exploring peptide support for their dog can review K9-REPAIR — BPC-157 + TB-500 formulated for dogs — at https://pawgen.com/. BPC-157 and TB-500 are not FDA-approved veterinary drugs. Nothing in this article treats, cures or prevents any condition; every decision about your dog's care belongs with your veterinarian.