Old Dog Diarrhea and Peeing A Lot (Here’s Why)

Old Dog Diarrhea and Peeing a Lot: Common Causes 

1. Kidney Disease

One of the most common causes of increased urination in senior dogs is chronic kidney disease.

The kidneys help filter toxins and maintain fluid balance in the body.

When they start to fail, they can’t concentrate urine properly, causing your dog to urinate more frequently.

Chronic kidney disease can also lead to gastrointestinal upset, including diarrhea in old dogs, due to the buildup of waste products in the blood. Symptoms may include:

• Increased thirst and urination

• Vomiting or nausea

• Lethargy

• Weight loss

• Pale gums

If your old dog has diarrhea and is peeing a lot, kidney issues should be high on the list of possible causes.

Related: Old dog diarrhea and blood (Causes and treatment)

2. Diabetes in Older Dogs

Diabetes mellitus can also cause an old dog to have diarrhea and pee a lot.

This condition occurs when the body can’t properly regulate blood sugar levels, leading to excessive glucose in the bloodstream.

Increased urination (polyuria) and increased thirst (polydipsia) are hallmark signs of diabetes.

Some diabetic dogs also experience gastrointestinal symptoms like diarrhea, either from the disease itself or related conditions like pancreatitis.

Signs of diabetes include:

• Frequent urination

• Sudden weight loss despite normal or increased appetite

• Cloudy eyes (cataracts)

• Fatigue

• Diarrhea or vomiting

Early detection is crucial to managing diabetes in older dogs effectively.

3. Cushing’s Disease (Hyperadrenocorticism)

Cushing’s disease is caused by an overproduction of cortisol, a hormone that regulates various body functions.

It commonly affects middle-aged and older dogs and can lead to increased urination, thirst, and digestive upset.

Symptoms of Cushing’s disease may include:

• Pot-bellied appearance

• Hair loss

• Thinning skin

• Muscle weakness

• Old dog diarrhea and peeing a lot

Because Cushing’s affects multiple systems, it can be tricky to diagnose without blood tests and imaging, so veterinary evaluation is key.

4. Urinary Tract Infections (UTIs)

In older dogs, UTIs can occur more frequently, especially in females or those with underlying conditions like diabetes.

While UTIs typically cause frequent urination, they can also trigger mild gastrointestinal upset or worsen existing diarrhea.

Watch for:

• Frequent attempts to urinate with small amounts

• Bloody or cloudy urine

• Licking the urinary opening

• Discomfort while urinating

• Occasional diarrhea

If your old dog is having diarrhea and peeing a lot, and seems to strain or cry while urinating, a UTI could be to blame.

5. Liver Disease

Liver disease in senior dogs can disrupt normal digestion and increase the frequency of urination.

The liver plays a critical role in processing waste and synthesizing nutrients, and its decline can lead to a host of symptoms.

These may include:

• Diarrhea or greasy stools

• Increased thirst and urination

• Jaundice (yellowing of eyes or gums)

• Loss of appetite

• Confusion or disorientation (hepatic encephalopathy)

If you’re noticing changes in your old dog’s bathroom habits, including both diarrhea and excessive urination, liver function should be considered.

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

6. Medication Side Effects

Older dogs are often on medications for conditions like arthritis, heart problems, or cognitive decline.

Some of these medications can have side effects, including diarrhea in old dogs and increased urination.

Common culprits include:

• Steroids (prednisone)

• Diuretics (furosemide)

• Anti-inflammatories

• Antibiotics

If your senior dog recently started a new medication and is now experiencing diarrhea and urinating frequently, consult your vet to evaluate whether the meds might be the cause.

7. Dietary Indiscretion or Sensitivities

Even older dogs can have moments of bad judgment—like sneaking into the trash or gobbling up human food.

This can lead to short-term diarrhea and frequent peeing, especially if the ingested food is salty or spicy, which increases thirst and urination.

Senior dogs may also develop new food sensitivities.

Switching diets abruptly or introducing unfamiliar treats can irritate their aging digestive systems.

To minimize the risk:

• Stick to a consistent, high-quality senior dog food

• Avoid table scraps

• Gradually transition between food types

If your old dog has diarrhea and pees a lot after a recent diet change, that may be the root cause.

8. Cognitive Dysfunction Syndrome (Dog Dementia)

In some cases, an older dog may start to pee frequently or have accidents with diarrhea due to canine cognitive dysfunction (CCD).

This age-related decline in mental function can make them forget housetraining rules or become disoriented.

Signs of CCD include:

• Pacing or wandering

• Forgetting routines

• Barking at nothing

• Disorientation

• Incontinence or house soiling

Though CCD doesn’t directly cause diarrhea, the stress and confusion it brings can contribute to digestive upset in some dogs.

What to Do If Your Old Dog Has Diarrhea and Is Peeing a Lot

If you notice your old dog experiencing both diarrhea and peeing a lot, there are several steps to take:

1. Observe Closely

Monitor your dog’s symptoms, including:

• How often they’re urinating

• Stool color and consistency

• Any signs of blood in urine or stool

• Changes in appetite or energy

• Vomiting, disorientation, or shaking

Keep a symptom diary if needed to share with your veterinarian.

2. Hydration Is Critical

Diarrhea and increased urination can lead to dehydration quickly, especially in senior dogs.

Make sure your dog has constant access to clean, fresh water. Watch for signs of dehydration such as:

• Sunken eyes

• Dry mouth or gums

• Lethargy

• Skin losing elasticity

If dehydration is suspected, seek veterinary care immediately.

3. Don’t Medicate Without a Vet

Avoid giving over-the-counter anti-diarrheal or urinary tract medications unless prescribed by a vet.

These can worsen some conditions or interact with other medications your dog may be on.

4. Get a Veterinary Diagnosis

Schedule a veterinary appointment as soon as possible. Diagnostic tests may include:

• Urinalysis

• Blood panel

• Fecal exam

• X-rays or ultrasound

• Hormone testing

Getting to the root cause of your old dog’s diarrhea and increased peeing is essential to determine the right treatment.

When to Seek Immediate Help

Contact your vet or emergency clinic right away if your senior dog shows:

• Bloody diarrhea or urine

• Severe lethargy or collapse

• Vomiting combined with diarrhea

• Signs of pain or abdominal swelling

• Not urinating at all or straining

• Sudden weight loss

These may be signs of a serious or life-threatening condition requiring immediate attention.

Key Takeaway

Old dog diarrhea and peeing a lot can be a sign of various health conditions, from mild and temporary to serious and chronic.

While it’s easy to brush off as part of aging, these symptoms deserve attention—especially if they appear suddenly or persist for more than a day.

Early detection and professional care are the best ways to ensure your senior dog stays comfortable, healthy, and by your side for as long as possible.

If in doubt, always consult your veterinarian.