Vomiting and Diarrhea in Pets: A Pet Parent’s Guide to What’s Normal and What’s No

Few things worry pet owners more than seeing their cat or dog struggle with an upset stomach. Occasional tummy troubles may not be a big deal, but persistent vomiting and diarrhea in pets can point to something more serious. The challenge for most pet parents is knowing when to wait it out and when it's time to head to the vet. This guide will help you recognize the difference and take the right steps to keep your furry friend safe.
Why Pets Get Vomiting or Diarrhea
Digestive issues in pets are surprisingly common, and they can stem from something as simple as stealing food from the trash to more complicated health conditions. Common triggers include:

• Dietary indiscretion - Eating spoiled food, garbage, or unfamiliar treats can quickly upset the stomach.
• Infections - Viruses, bacteria, or parasites like giardia may cause repeated vomiting and loose stools.
• Food intolerance or allergies - Some pets react poorly to certain proteins or additives in commercial foods.
• Toxins - Substances like chocolate, grapes, medications, or chemicals can lead to dangerous reactions.
• Underlying conditions - Chronic illnesses such as pancreatitis, kidney disease, or liver disorders can show up first as digestive distress.

Warning Signs That It's More Than a Simple Upset Stomach
Not every bout of vomiting or diarrhea requires a trip to the emergency clinic. But there are red flags you should never ignore. Contact a vet if your pet shows:
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10 Warning Signs of Stomach Cancer in Dogs You Should Watch For

Skipping meals, frequent vomiting, or showing discomfort after eating might seem like minor stomach issues. But in some cases, these subtle changes can point to something much more serious—stomach cancer. The most common forms, such as gastric adenocarcinoma and lymphoma, are aggressive diseases. Recognizing the signs early gives your dog the best chance at treatment success and a better quality of life.
What exactly is stomach cancer in dogs?
Stomach cancer occurs when abnormal cells in the lining of the stomach grow uncontrollably and form tumors. These growths may cause internal bleeding, block digestion, and sometimes spread to organs like the liver or lymph nodes. Though relatively rare, it is a life-threatening condition most often diagnosed in middle-aged or senior dogs.
10 signs that deserve immediate attention
Because the early symptoms mimic routine digestive upsets, it's important for owners to watch for patterns that persist. Below are ten warning signs that should not be overlooked:
1. Ongoing appetite loss
If your dog refuses food for several days in a row—even favorite meals or treats—it could indicate more than just fussiness. Stomach cancer–related appetite loss usually doesn't improve with changes in food or feeding schedule.
2. Sudden and unexplained weight loss
A rapid drop in body weight of 10% or more is a red flag. You may notice more prominent ribs or hips and reduced muscle mass around the back legs.
3. Frequent vomiting
Throwing up multiple times a week, especially long after meals, is concerning. Vomit that contains blood (bright red or coffee-ground–like) signals internal bleeding and requires urgent care.
4. Subtle but consistent belly pain
Dogs may take on a “prayer position,” move stiffly, or avoid being touched on the stomach if in pain. These behaviors may start mild but usually worsen over time.
5. Black or tarry stools (melena)
Dark, sticky stools with a metallic smell are often caused by bleeding in the upper digestive system. Taking a photo can help your veterinarian assess the severity.
6. Trouble swallowing or regurgitating food
If food comes back up shortly after eating or your dog repeatedly adjusts their neck to swallow, a tumor may be blocking the passageway between the esophagus and stomach.
7. Loss of energy
Excessive sleep, avoiding walks, or tiring quickly are signs that your dog is not feeling well. Compare current activity levels to your pet's usual routine to spot changes.
8. Noticeable bloating or swelling
A stomach that feels tight or swollen may result from tumor growth, gas buildup, or fluid retention. If bloating occurs suddenly and your dog cannot vomit, treat it as an emergency.
9. Heavy drooling and unpleasant breath
Excessive saliva or a metallic, foul odor often point to reflux or infection linked to stomach disease.
10. Changes in drinking habits
Both increased thirst (due to dehydration) or reduced drinking (from nausea) are red flags. Track your dog's water intake and share any sudden changes with your vet.
Emergency red flags: Seek urgent veterinary help if your dog vomits blood repeatedly, collapses, has pale gums, struggles to breathe, or shows sudden severe bloating.
When should you visit the vet?
If you notice multiple warning signs or a single symptom that lasts more than five days, schedule a veterinary exam right away. Regular checkups are also useful for catching early changes before they become severe.
Why quick action makes a difference
Stomach cancer in dogs progresses quickly, but early detection allows for more treatment options and can extend your dog's comfort and lifespan. If your pet shows persistent vomiting, appetite loss, weight loss, or other concerning changes, don't delay a vet visit—early action truly matters.
Learn more about canine stomach health at Kainer Veterinary Hospital.
At Kainer Veterinary Hospital, we provide compassionate, expert care for pets facing cancer and other serious conditions. To book an appointment or ask about symptoms, contact us or call (936) 321-2000.

10 Warning Signs of Stomach Cancer in Dogs You Should Watch For

Skipping meals, frequent vomiting, or showing discomfort after eating might seem like minor stomach issues. But in some cases, these subtle changes can point to something much more serious—stomach cancer. The most common forms, such as gastric adenocarcinoma and lymphoma, are aggressive diseases. Recognizing the signs early gives your dog the best chance at treatment success and a better quality of life.
What exactly is stomach cancer in dogs?
Stomach cancer occurs when abnormal cells in the lining of the stomach grow uncontrollably and form tumors. These growths may cause internal bleeding, block digestion, and sometimes spread to organs like the liver or lymph nodes. Though relatively rare, it is a life-threatening condition most often diagnosed in middle-aged or senior dogs.
10 signs that deserve immediate attention
Because the early symptoms mimic routine digestive upsets, it's important for owners to watch for patterns that persist. Below are ten warning signs that should not be overlooked:
1. Ongoing appetite loss
If your dog refuses food for several days in a row—even favorite meals or treats—it could indicate more than just fussiness. Stomach cancer–related appetite loss usually doesn't improve with changes in food or feeding schedule.
2. Sudden and unexplained weight loss
A rapid drop in body weight of 10% or more is a red flag. You may notice more prominent ribs or hips and reduced muscle mass around the back legs.
3. Frequent vomiting
Throwing up multiple times a week, especially long after meals, is concerning. Vomit that contains blood (bright red or coffee-ground–like) signals internal bleeding and requires urgent care.
4. Subtle but consistent belly pain
Dogs may take on a “prayer position,” move stiffly, or avoid being touched on the stomach if in pain. These behaviors may start mild but usually worsen over time.
5. Black or tarry stools (melena)
Dark, sticky stools with a metallic smell are often caused by bleeding in the upper digestive system. Taking a photo can help your veterinarian assess the severity.
6. Trouble swallowing or regurgitating food
If food comes back up shortly after eating or your dog repeatedly adjusts their neck to swallow, a tumor may be blocking the passageway between the esophagus and stomach.
7. Loss of energy
Excessive sleep, avoiding walks, or tiring quickly are signs that your dog is not feeling well. Compare current activity levels to your pet's usual routine to spot changes.
8. Noticeable bloating or swelling
A stomach that feels tight or swollen may result from tumor growth, gas buildup, or fluid retention. If bloating occurs suddenly and your dog cannot vomit, treat it as an emergency.
9. Heavy drooling and unpleasant breath
Excessive saliva or a metallic, foul odor often point to reflux or infection linked to stomach disease.
10. Changes in drinking habits
Both increased thirst (due to dehydration) or reduced drinking (from nausea) are red flags. Track your dog's water intake and share any sudden changes with your vet.
Emergency red flags: Seek urgent veterinary help if your dog vomits blood repeatedly, collapses, has pale gums, struggles to breathe, or shows sudden severe bloating.
When should you visit the vet?
If you notice multiple warning signs or a single symptom that lasts more than five days, schedule a veterinary exam right away. Regular checkups are also useful for catching early changes before they become severe.
Why quick action makes a difference
Stomach cancer in dogs progresses quickly, but early detection allows for more treatment options and can extend your dog's comfort and lifespan. If your pet shows persistent vomiting, appetite loss, weight loss, or other concerning changes, don't delay a vet visit—early action truly matters.
Learn more about canine stomach health at Kainer Veterinary Hospital.
At Kainer Veterinary Hospital, we provide compassionate, expert care for pets facing cancer and other serious conditions. To book an appointment or ask about symptoms, contact us or call (936) 321-2000.

How to Deal with Severe Vomiting and Diarrhea in Pets: When to Seek Emergency Care

As pet owners, it can be distressing to see your pet experience vomiting and diarrhea, especially when it’s severe. While mild cases of gastrointestinal upset can often be managed at home, there are times when these symptoms can indicate a more serious underlying condition that requires emergency care for pets.
In this blog, we’ll discuss how to recognize when vomiting and diarrhea in pets is a cause for concern, how to provide initial care at home, and when you should seek urgent veterinary care to prevent complications.
Why Vomiting and Diarrhea Occur in Pets
There are many reasons pets might experience vomiting and diarrhea, ranging from something as simple as a change in diet to more serious medical conditions. Understanding the root cause can help you determine the severity and urgency of the situation. Common causes include:

• Dietary indiscretion: Pets are curious creatures, and they often eat things they shouldn’t, including spoiled food, garbage, or foreign objects, leading to gastrointestinal distress.
• Infections: Viral, bacterial, or parasitic infections can cause vomiting and diarrhea in pets. Examples include parvovirus in puppies or bacterial infections like Salmonella.
• Food allergies or sensitivities: Some pets may have adverse reactions to certain ingredients in their food, leading to digestive upset.
• Toxins: Ingesting harmful substances like household chemicals, human medications, plants, or certain foods (like chocolate or grapes) can cause vomiting and diarrhea.
• Stress: Changes in environment, such as travel, moving homes, or even the addition of new family members, can trigger gastrointestinal upset in pets.
• Chronic diseases: Conditions like kidney disease, liver disease, pancreatitis, and inflammatory bowel disease can cause recurrent vomiting and diarrhea.

While most cases of vomiting and diarrhea are not life-threatening, severe or persistent symptoms can be a sign of a more serious health issue that needs to be addressed right away.
Recognizing the Severity of Vomiting and Diarrhea in Pets
The severity and frequency of vomiting and diarrhea are crucial factors in determining whether your pet needs emergency care. Here’s how to assess the situation:
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Early Signs of Stomach Cancer in Dogs Every Pet Parent Should Know

If your dog suddenly loses interest in food, vomits often, or seems uncomfortable after meals, it could be more than just an upset stomach. These subtle changes may point to something serious, such as stomach cancer in dogs. Although it’s not very common, this condition especially forms like gastric adenocarcinoma or gastric lymphoma in dogs can be life-threatening if not caught early.
This guide will help you recognize the 10 critical warning signs of stomach cancer in dogs, understand when to seek emergency care, and learn what treatment options are available to help your dog live comfortably.
What is Stomach Cancer in Dogs?
Stomach cancer occurs when malignant cells multiply uncontrollably in the gastric lining, forming tumors that disrupt digestion, cause bleeding, and spread to nearby organs like the liver and lymph nodes.
Stomach cancer affects approximately 8,000 dogs annually in the United States. The most common type, adenocarcinoma, makes up 70% of all gastric tumors in dogs. These tumors typically develop in dogs aged 7-12 years, with certain breeds showing higher susceptibility than others.
10 Early Signs of Stomach Cancer in Dogs
Ten critical symptoms distinguish stomach cancer from minor digestive issues: persistent appetite loss lasting 5+ days, unexplained weight loss exceeding 10%, chronic vomiting, abdominal pain, bloody stools, swallowing difficulty, lethargy, bloating, excessive drooling, and altered drinking patterns.
1. Loss of Appetite That Won’t Go Away
Your dog suddenly shows no interest in food for more than 5 consecutive days. Unlike typical pickiness, they may approach their food bowl but walk away after sniffing, or refuse even their favorite treats. Normal dogs consume 2-3% of their body weight daily, but dogs with stomach cancer reduce their intake by 50-70%.
What makes this different from normal appetite changes: The loss of appetite doesn’t improve with different foods, feeding schedules, or encouragement.
2. Unexplained Weight Loss
You notice your dog losing 10% or more of their body weight within a month, despite maintaining their normal feeding routine. Their ribs become more visible, and muscle mass decreases noticeably around their hindquarters and spine. This isn’t gradual seasonal weight change—it’s rapid, unexplained loss that continues week after week.
What to watch for: Feel along your dog’s ribs and spine monthly. These areas should have a thin fat layer, not prominent bone protrusion.
3. Vomiting More Than Usual
Your dog vomits 3 or more times per week, often several hours after eating. The vomit may contain blood (bright red) or have a coffee-ground appearance (partially digested blood). Normal dogs vomit occasionally due to eating too fast or dietary indiscretion, but cancer-related vomiting is persistent and doesn’t improve with dietary changes.
Red flag symptoms: Any blood in vomit requires immediate veterinary attention.
4. Signs of Stomach Pain
Dogs with gastric tumors display subtle pain signals that gradually become more obvious. They may assume a “prayer position” with their chest down and hindquarters up, especially when the pain is severe. You might notice they’re sensitive when you touch their belly area, or they walk with a hunched back and shortened steps.
Behavioral changes indicating pain:

• Reluctance to jump on furniture or climb stairs
• Seeking soft surfaces for lying down
• Frequently changing positions while resting
• Shallow, rapid breathing

5. Black, Tarry Stools (Melena)
Normal dog stool is brown and firm, but stomach bleeding creates black, tar-like stools with a sticky consistency and strong metallic odor. This happens when blood from gastric ulcers gets partially digested as it moves through the intestines. Fresh red blood in stool indicates bleeding lower in the digestive tract.
Important: Take photos of abnormal stools to show your veterinarian, as they help determine the bleeding location.
6. Difficulty Swallowing
Your dog makes repeated gulping motions when trying to swallow food, or food comes back up within 30 minutes of eating (regurgitation). Dogs may change their head position frequently while eating or prefer elevated feeding positions. Liquid consumption often becomes easier than eating solid food.
What causes this: Tumors in the upper stomach can block the connection between the esophagus and stomach.
7. Extreme Tiredness and Low Energy
Your previously active dog now sleeps 16+ hours daily and shows 60-80% less activity than their normal baseline. Walking distances decrease dramatically—from miles to just a few blocks—and they need frequent rest breaks during previously routine activities.
Track changes: Note your dog’s normal walking distance and energy levels to identify gradual decreases.
8. Bloated or Swollen Belly
The stomach area appears visibly swollen, feeling tight and drum-like when touched. This happens as tumors take up space normally reserved for food and gas. Breathing may become labored due to pressure against the diaphragm.
Emergency warning: Sudden, severe bloating combined with unsuccessful attempts to vomit requires immediate veterinary care.
9. Excessive Drooling and Bad Breath
Your dog produces more saliva than normal, and their breath develops a particularly foul or metallic smell that’s worse than typical “dog breath.” Stomach tumors can cause acid reflux that irritates the throat and creates conditions for bacterial overgrowth in the mouth.
10. Changes in Water Drinking
Your dog either drinks significantly more water than usual (150-200% increase) due to dehydration from vomiting, or drinks much less (50% decrease) because they associate drinking with feeling nauseous afterward.
Normal water intake: Dogs typically drink 0.5-1 ounce per pound of body weight daily. Learn more about how hydration impacts your pet’s health.
When to See Your Veterinarian Immediately
Emergency intervention becomes necessary when dogs collapse, vomit blood continuously, show pale gums indicating anemia, experience difficulty breathing, or demonstrate severe abdominal distension suggesting gastric rupture or obstruction.
Seek emergency care if your dog shows:

• Continuous vomiting with blood
• Pal or white gums
• Collapse or inability to stand
• Severe bloating with unsuccessful vomiting attempts
• Difficulty breathing
• Body temperature below 99°F or above 103°F

Schedule an exam within 24-48 hours if your dog has:

• Multiple symptoms from the list above
• Any single symptom lasting more than 5 days
• Combination of appetite loss and weight loss
• Black, tarry stools

Regular wellness exams can help detect early warning signs before they become emergencies.
Taking Action for Your Dog’s Health
Stomach cancer in dogs is a serious condition that requires prompt attention and expert care. By recognizing these early warning signs and seeking immediate veterinary evaluation, you can help ensure the best possible outcome for your beloved companion. Don’t wait when you notice persistent vomiting, appetite loss, or other concerning symptoms, early detection can transform a devastating diagnosis into manageable treatment options.
At Kainer Veterinary Hospital, we are committed to providing comprehensive cancer care with the compassion and expertise your pet deserves. If your dog shows any signs of stomach cancer, don’t hesitate to schedule an appointment by contacting us or calling (936) 321‑2000. We're here to help guide you through every step of your dog’s health journey.