When an old dog is vomiting and drinking lots of water, it can raise serious concerns for pet owners.
Vomiting in older dogs isn’t always just about a bad meal—it can be a signal of a deeper health problem, especially when paired with excessive thirst.
We outline the common causes of old dog vomiting and drinking lots of water, why these symptoms may happen together, and what you can do to help your aging furry friend.
Old Dog Vomiting and Drinking Lots of Water: Why It Happens
Old dog vomiting and drinking lots of water are a combination of symptoms that often signal an underlying health issue in senior dogs. As dogs age, their organs—especially the kidneys, liver, and pancreas—become more vulnerable to disease.
Conditions like kidney failure, diabetes, liver disease, and Cushing’s disease can lead to both vomiting and increased thirst.
Vomiting causes fluid loss, which triggers thirst, while some illnesses increase water consumption directly due to toxin buildup or hormonal imbalances.
Additionally, medication side effects, gastrointestinal issues, or even stress can cause these symptoms.
In older dogs, prompt veterinary evaluation is essential to identify and manage the root cause.
Old Dog Vomiting and Drinking Lots of Water: Common Causes
1. Kidney Disease
One of the most common reasons behind an old dog vomiting and drinking lots of water is chronic kidney disease.
As dogs age, their kidney function naturally declines.
When the kidneys can no longer filter toxins from the blood effectively, the body attempts to flush these toxins out through increased urination.
In turn, the dog drinks more water to compensate for fluid loss. Vomiting occurs because the buildup of toxins irritates the stomach and triggers nausea.
If your senior dog is vomiting and drinking excessively, along with signs such as weight loss, lethargy, and bad breath, kidney disease may be to blame.
2. Diabetes Mellitus
Diabetes is another condition that can cause both vomiting and increased thirst in older dogs.
When the dog’s body can’t regulate blood sugar properly, glucose builds up in the bloodstream.
This leads to excessive urination and thirst.
Vomiting may result from diabetic ketoacidosis (DKA), a dangerous complication of uncontrolled diabetes where the body breaks down fat too quickly, leading to acid buildup in the blood.
If your old dog is vomiting and drinking lots of water and also has sweet-smelling breath or unexplained weight loss, diabetes should be ruled out immediately by a vet.
3. Cushing’s Disease
Cushing’s disease (hyperadrenocorticism) is a hormonal disorder that’s especially common in older dogs.
It causes the adrenal glands to produce too much cortisol, leading to increased thirst, frequent urination, and a pot-bellied appearance.
Vomiting can occur due to secondary infections, ulcers, or pancreatitis—conditions often triggered by elevated cortisol levels.
In an old dog vomiting and drinking lots of water, combined with hair thinning or a bloated abdomen, Cushing’s disease should be considered.
4. Liver Disease
A senior dog’s liver plays a crucial role in detoxification and digestion.
When the liver begins to fail, toxins accumulate in the bloodstream, which can make a dog feel nauseated and vomit.
At the same time, liver dysfunction can cause changes in the dog’s metabolism, triggering increased thirst.
Common symptoms of liver disease, along with vomiting and drinking lots of water, include jaundice (yellowing of the eyes or gums), confusion, and dark-colored urine.
Related: Old dog diarrhea and vomiting (Causes and treatment)
5. Gastrointestinal Disorders
Various digestive issues can cause an old dog to vomit. Chronic gastritis, inflammatory bowel disease, or even tumors in the GI tract can make a dog vomit frequently.
If vomiting leads to fluid loss, the dog may instinctively drink lots of water to stay hydrated.
However, gulping too much water at once can sometimes lead to further vomiting.
If your older dog is vomiting and drinking excessively, and also shows signs like bloating or bloody vomit, a gastrointestinal problem may be the underlying issue.
6. Dehydration Due to Vomiting
Sometimes, the sequence is reversed: vomiting comes first, and then the excessive water intake follows.
When an old dog vomits, they lose not only food but also fluids and electrolytes.
This triggers thirst and causes the dog to drink more water in an attempt to rehydrate.
Unfortunately, drinking too quickly can sometimes cause more vomiting, creating a frustrating cycle.
This scenario is particularly common when dogs eat something that doesn’t agree with them or catch a mild stomach bug.
7. Medication Side Effects
Senior dogs often take medications for arthritis, heart issues, or other chronic conditions.
Some of these drugs, especially NSAIDs and steroids, can irritate the stomach lining and lead to vomiting.
Others may increase thirst as a side effect.
If your old dog is vomiting and drinking lots of water shortly after starting a new medication, consult your veterinarian.
Keep an eye on dosage instructions, and never give over-the-counter medications without professional guidance.
Related: Old dog vomiting and losing weight (Causes, triggers and Prevention)
8. Poisoning or Ingestion of Toxins
Older dogs may still get into harmful substances, especially if they are experiencing cognitive decline.
Ingesting something toxic—like chocolate, certain plants, or human medications—can cause sudden vomiting and dehydration.
To cope with fluid loss or internal irritation, the dog may begin drinking water excessively.
Toxicity can escalate quickly, so if your old dog is vomiting and drinking lots of water after being around a suspicious substance, it’s a medical emergency.
9. Heatstroke or Overheating
Although heatstroke is more common in younger, energetic dogs, older dogs with mobility or breathing issues are not immune.
Vomiting and drinking lots of water can be signs that your dog is overheated. If left untreated, heatstroke can lead to organ damage or even death.
If your senior dog has been in a hot environment and shows these symptoms along with panting or collapse, seek help right away.
What to Do If Your Old Dog Is Vomiting and Drinking Lots of Water
Knowing what to do when your old dog is vomiting and drinking lots of water can make all the difference in recovery.
Here are key steps to take:
1. Don’t wait it out
While occasional vomiting might not be serious, consistent vomiting paired with increased thirst in an older dog is cause for concern.
Don’t assume it will resolve on its own—older dogs can become dehydrated quickly.
2. Monitor their behavior
Watch for additional symptoms like lethargy, diarrhea, appetite loss, confusion, or changes in urination.
Take note of how frequently your dog is vomiting, what the vomit looks like (clear, yellow, food-based, bloody), and how much water they are consuming.
3. Remove access to toxins
Ensure your dog hasn’t gotten into cleaning products, pesticides, or spoiled food.
If you suspect poisoning, go to the vet immediately.
4. Provide small sips of water
If your dog is vomiting, limit water intake to small, frequent sips rather than allowing them to gulp large amounts.
Drinking too much too fast can trigger more vomiting.
5. Offer a bland diet (with vet approval)
If vomiting is mild and your vet approves, you can try feeding small amounts of boiled chicken and rice.
However, if symptoms persist for more than 24 hours or worsen, skip home remedies and get professional help.
6. Visit your veterinarian
Ultimately, the safest course of action is to schedule a vet visit.
Blood tests, urinalysis, and imaging (such as X-rays or ultrasound) can help identify conditions like kidney failure, diabetes, or gastrointestinal blockages.
When to Seek Immediate Veterinary Help
Certain warning signs indicate that the situation is urgent.
Seek emergency veterinary care if your old dog is vomiting and drinking lots of water and:
Vomiting contains blood or looks like coffee grounds
There’s diarrhea with blood or mucus
Your dog is listless or non-responsive
They stop eating entirely
They collapse or appear disoriented
They have a history of chronic illness like diabetes or kidney disease
Prompt treatment can prevent complications and improve your dog’s prognosis.
Key Takeaway
Old dog vomiting and drinking lots of water is not a symptom pair to take lightly.
These signs often indicate that your aging pet may be dealing with kidney issues, diabetes, liver disease, or another chronic health problem.
In some cases, the issue may be mild and resolve quickly—but in older dogs, it’s always better to err on the side of caution.
If your dog is displaying these symptoms, monitor their behavior closely and consult your veterinarian.
With timely diagnosis and treatment, many of the conditions causing vomiting and excessive thirst in senior dogs can be managed effectively, improving your dog’s quality of life in their golden years.