Understanding the Gut

Exocrine Pancreatic Insufficiency in Dogs: What Is EPI?

Exocrine pancreatic insufficiency, or EPI, occurs when the pancreas does not produce enough digestive enzymes. Dogs may lose weight despite eating well and can pass large volumes of loose stools, so veterinary diagnosis and enzyme replacement are important.

Introduction

Exocrine pancreatic insufficiency, usually shortened to EPI, is a condition in which the pancreas does not produce or release enough digestive enzymes.

Those enzymes are important because they help break down protein, fat and carbohydrate so nutrients can be absorbed.

When enzyme production falls dramatically, food may not be digested properly.

Dogs with EPI can therefore lose weight even when they are eating normally or appear unusually hungry.

They may also produce large volumes of loose, pale or particularly strong-smelling stools.

EPI requires veterinary diagnosis and treatment. It is not simply a sensitive stomach or a minor digestive upset.

Understanding the issue

What is happening?

The pancreas has an important role in digestion.

Its exocrine portion produces digestive enzymes including amylase, lipase and proteases.

These enzymes are released into the small intestine, where they help break down carbohydrates, fats and proteins.

In EPI, pancreatic enzyme production becomes severely reduced.

As a result, food entering the small intestine cannot be digested as effectively.

More undigested nutrients remain within the gastrointestinal tract, contributing to poor nutrient absorption and altered stools.

The pancreas also contributes to vitamin B12 absorption by producing intrinsic factor.

For that reason, dogs with EPI can also develop low vitamin B12, or cobalamin, levels.

EPI is therefore fundamentally a problem of digestion and nutrient assimilation.

Common factors

What can influence it?

Different underlying processes can lead to EPI.

Pancreatic acinar atrophy

This is a common cause in breeds including German Shepherd Dogs, Rough Collies and Eurasiers.

Chronic pancreatitis

Long-term pancreatic inflammation can gradually damage the tissue responsible for producing digestive enzymes.

Breed predisposition

Some breeds appear to have a greater risk of particular forms of EPI.

Age

Dogs with pancreatic acinar atrophy may develop EPI as young adults, while EPI associated with chronic pancreatitis may occur later in life.

Loss of pancreatic tissue

Clinical signs usually appear only after a very large proportion of pancreatic digestive capacity has been lost.

The underlying cause can therefore differ considerably between individual dogs.

What you may notice

What can you observe?

Owners may notice several characteristic patterns.

Weight loss

One of the most important signs is losing weight despite eating an apparently adequate amount of food.

Increased appetite

Some dogs appear constantly hungry because nutrients are not being absorbed normally.

Large-volume stools

Stools may become noticeably more voluminous than usual.

Loose stools

Faeces can be soft or poorly formed.

Pale or unusually strong-smelling stools

Stool appearance and smell may change substantially.

Difficulty maintaining body condition

Dogs can become noticeably thin even when food intake seems high.

Changes in coat or general condition

Long-term poor nutrient absorption can affect overall condition.

These signs are not unique to EPI, so diagnosis requires specific veterinary testing.

Everyday considerations

If your dog has been diagnosed with EPI, consistency in management is important.

Treatment normally involves pancreatic enzyme replacement with meals.

Your vet may also recommend vitamin B12 supplementation and dietary changes depending on your dog's individual needs.

Enzyme replacement is usually required long term.

Do not replace prescribed pancreatic enzymes with ordinary digestive supplements.

Pancreatic enzyme replacement therapy is specifically intended to compensate for the enzyme secretion the pancreas can no longer provide.

It can also be helpful to monitor:

body weight
stool consistency
appetite
frequency of bowel movements
body condition

Once treatment is working well, many dogs can return to good body condition and normal stool quality.

When to speak to your vet

Speak to your vet if your dog is losing weight despite eating well, develops persistent large-volume loose stools or seems unusually hungry.

Veterinary assessment is particularly important if you notice:

unexplained weight loss
persistent diarrhoea
unusually large amounts of stool
a marked increase in appetite
difficulty maintaining body condition
recurrent gastrointestinal signs
vomiting
weakness or lethargy

EPI is usually diagnosed using a blood test called serum trypsin-like immunoreactivity, or TLI.

Your vet may also test vitamin B12 and folate levels because deficiencies can occur alongside EPI.

Once diagnosed, appropriate treatment can be very effective.

References

Further reading:

Steiner JM. Exocrine Pancreatic Insufficiency in Dogs and Cats. Merck Veterinary Manual. Reviewed September 2025.

Steiner JM. Pancreatitis and Other Disorders of the Pancreas in Dogs. Merck Veterinary Manual.

Batchelor DJ, Noble PJ, Taylor RH, Cripps PJ, German AJ. Prognostic factors in canine exocrine pancreatic insufficiency: prolonged survival is likely if clinical remission is achieved. Journal of Veterinary Internal Medicine. 2007;21(1):54–60.

Barko PC, Williams DA. Serum concentrations of lipid-soluble vitamins in dogs with exocrine pancreatic insufficiency treated with pancreatic enzymes. Journal of Veterinary Internal Medicine. 2018;32(5):1600–1608.

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