Old Dog Diarrhea and Vomiting: Causes and Solutions

Common Causes of Diarrhea and Vomiting in Old Dogs

1. Dietary Indiscretion or Sudden Change in Diet

Just like in younger dogs, sudden changes in food can disrupt the gastrointestinal balance in older dogs.

However, aging dogs have more sensitive stomachs and slower metabolism, making them even more susceptible.

• Eating spoiled food or table scraps

• Sudden switch in dog food brand or formula

• Overindulgence in fatty or rich treats

This can lead to both diarrhea and vomiting in old dogs, especially if their digestion is already compromised.

Related: Old dog diarrhea and not eating (Here’s why)

2. Chronic Illness and Organ Dysfunction

Senior dogs are at increased risk for chronic diseases that can cause gastrointestinal upset, including:

• Kidney disease

• Liver disease

• Pancreatitis

• Cancer or tumors of the digestive tract

In these cases, old dog vomiting and diarrhea may be chronic, intermittent, or occur alongside symptoms like loss of appetite, lethargy, or weight loss.

3. Infections (Viral, Bacterial, or Parasitic)

While older dogs may have had vaccinations earlier in life, their immune response weakens with age, making them vulnerable to:

• Parvovirus (rare in vaccinated dogs, but still a risk)

• Giardia and Coccidia

• Clostridium, Salmonella, or other bacteria

Such infections can inflame the gastrointestinal lining, leading to vomiting, diarrhea, and sometimes blood in the stool.

Related: Old dog bloody diarrhea and vomiting (Here’s why)

4. Medications and Their Side Effects

Many older dogs are on medication for chronic conditions such as arthritis, heart disease, or epilepsy.

Certain drugs can irritate the gastrointestinal tract.

• NSAIDs (Non-Steroidal Anti-Inflammatory Drugs)

• Antibiotics

• Steroids

These medications may cause vomiting and diarrhea in senior dogs, especially when taken on an empty stomach or in incorrect dosages.

5. Toxin or Poison Ingestion

Older dogs may have impaired senses and reduced cognitive function, making them more likely to accidentally ingest harmful substances:

• Human medications

• Toxic plants

• Household cleaners

Toxins affect the digestive system and can lead to vomiting, diarrhea, trembling, or collapse.

Poisoning should always be treated as an emergency.

6. Gastrointestinal Disorders

Chronic conditions like Inflammatory Bowel Disease (IBD) or gastrointestinal ulcers often affect senior dogs. These issues can cause recurring diarrhea and vomiting, often worsening over time without treatment.

If your old dog has a history of digestive sensitivity, these disorders could be the root cause.

7. Stress and Anxiety

Even dogs can experience age-related cognitive decline and emotional stress. Things like:

• Changes in routine

• Separation anxiety

• Loud noises

• Moving homes

…can all affect older dogs more deeply. Stress-induced diarrhea and vomiting in old dogs are not uncommon and often appear suddenly.

8. Cancer (Gastrointestinal or Systemic)

Cancer is more prevalent in older dogs and may affect the gastrointestinal system or other organs that secondarily impact digestion.

Tumors in the stomach, liver, pancreas, or intestines can lead to chronic vomiting, bloody diarrhea, and severe weight loss.

If your dog is showing these symptoms and is not responding to basic treatment, a deeper diagnostic work-up is necessary.

Signs That Your Old Dog’s Vomiting and Diarrhea Need Immediate Attention

Not all cases are urgent, but with old dog vomiting and diarrhea, you need to be extra cautious.

Seek veterinary help if:

• Vomiting or diarrhea lasts more than 24 hours

• There is blood in the vomit or stool

• Your dog shows signs of dehydration (dry gums, sunken eyes, lethargy)

• There is a loss of appetite for more than a day

• Your dog collapses or becomes unresponsive

• Vomiting is projectile or occurs repeatedly in a short time

• Your dog has pre-existing health conditions

Old Dog Diarrhea and Vomiting: What to Do

If your old dog is vomiting and has diarrhea, quick action can prevent complications. Here’s what you should do:

1. Withhold Food for 12–24 Hours

Give your dog’s stomach a break. Stop feeding solid food for about 12 to 24 hours but do not restrict water—keep your dog hydrated.

However, if your dog is very old or frail, consult your vet before fasting.

2. Provide Access to Fresh Water

Vomiting and diarrhea cause significant fluid loss. Make sure your dog has access to clean, fresh water at all times. If your dog refuses to drink, try:

• Offering ice chips

• Giving water through a syringe

• Using electrolyte solutions for dogs

3. Feed a Bland Diet

After the fasting period, reintroduce food with a bland, easy-to-digest meal such as:

• Boiled chicken (no skin or seasoning)

• White rice or plain pasta

• Plain pumpkin (not pie filling)

Feed small, frequent meals and monitor how your dog responds.

4. Monitor Symptoms Closely

Take note of:

• Stool color and consistency

• Frequency of vomiting

• Water intake

• Appetite changes

• Behavior shifts (lethargy, confusion, trembling)

Keep this information handy for your vet.

5. Avoid Over-the-Counter Medications

Never give your dog human medications like Pepto Bismol or Imodium unless specifically directed by your vet.

These can worsen the situation or be toxic.

6. Visit the Vet

If symptoms persist or worsen, take your dog to the vet immediately. Your veterinarian may perform:

• Blood tests

• Stool sample analysis

• X-rays or ultrasounds

• Intravenous fluid therapy

• Prescription medications or special diets

Key Takeaway

While some causes of old dog diarrhea and vomiting are minor, others could be life-threatening.

Senior dogs are more prone to dehydration and complications, so early intervention is crucial.

Stay alert to warning signs, provide supportive care, and never hesitate to call your vet when symptoms persist.

Prompt attention could mean the difference between a mild upset and a serious medical emergency.

Your old dog deserves a comfortable, healthy life—and by being proactive, you can help make that happen.