What Does It Mean When the Vet Says My Dog Has High Liver Enzymes?

November 02, 2026 • After the Vet Visit • All Posts • Dogs • Health & Wellness • Liver Health

By Theresa Gibilisco, owner, The Hungry Puppy

"Your dog's liver enzymes came back a little high." It's a sentence that can follow you all the way home from the vet. People ask us at the counter what it means and whether they should change their dog's food tonight. The short answer: high liver enzymes are a clue, not a diagnosis, and the food plan depends on what your vet finds next.

Here's what the veterinary references say, in plain words. It's general information. Your vet has the final word on your dog's care and diet.

What are liver enzymes?

Liver enzymes are proteins that show up in a blood test, and higher than normal levels tell your vet to look more closely at the liver. Enzymes are proteins that help the body's chemistry along. When certain cells are stressed or damaged, some of these enzymes leak into the blood, and a routine blood panel picks that up.

The two you'll hear about most are ALT and ALP. They point in different directions, which is why your vet cares which one is high.

What's the difference between ALT and ALP?

ALT points to the liver cells themselves, while ALP points more toward bile flow and has more non-liver causes. Here's how a veterinary review in Today's Veterinary Practice describes them:

Enzyme	What it usually suggests	Other things that can raise it
ALT	Liver cells are being damaged. It's the most liver-specific of the liver enzymes.	Severe muscle damage
ALP	A problem with bile flowing out of the liver (vets call this cholestasis).	Young, growing dogs (a bone form of the enzyme), steroid medicines, and Cushing's disease

So a high ALP in a puppy, or in a dog taking a steroid medicine, can mean something very different from a high ALT in an older dog. Your vet reads them together with your dog's age, history and medicines.

Does high liver enzymes mean my dog has liver disease?

Not necessarily. The same review calls liver enzymes "sensitive but not necessarily specific" markers of liver disease. That means they're good at waving a flag, but the flag can go up for reasons outside the liver.

The review also says how high the numbers are doesn't reliably tell you how serious the problem is. A big number isn't automatically a disaster, and a small one isn't automatically nothing. That's why the next step matters more than the number itself.

What happens next?

Your vet will usually look for the cause before deciding on treatment or diet. Depending on your dog, the references mention steps like these:

A liver function test. Enzymes show irritation. A bile acids test shows how well the liver is actually working, and the review calls it arguably the best liver function test.
Looking at causes outside the liver. Steroid medicines and Cushing's disease (an overactive adrenal gland) can raise ALP in dogs.
Checking blood fats. Miniature Schnauzers with very high triglycerides (a type of blood fat) can have high liver enzymes too. See what it means when the vet says my dog has high triglycerides.
A liver biopsy, in some cases. A small tissue sample is how copper storage disease is diagnosed (more on that below).

Should I change my dog's food right away?

No, not on your own. A 2016 veterinary nutrition review says diet recommendations for liver disease depend on the dog's signs and the cause, and elevated enzymes alone aren't a diagnosis. Keep feeding the usual food in the usual amounts until your vet gives you a plan, unless your vet tells you otherwise.

Should a dog with liver problems eat less protein?

Usually not. The Merck Veterinary Manual says protein should be restricted only if a dog shows signs of hepatic encephalopathy, which means brain signs caused by toxins like ammonia that a struggling liver can't clear. Merck also lists one other reason: ammonium biurate crystals in the urine. Most dogs with long-term inflammatory liver disease should not have protein cut at diagnosis.

That 2016 review, in the Journal of the American Animal Hospital Association (JAAHA), agrees. It says to keep protein above 18% on a dry matter basis for dogs (about 51.4 grams per 1,000 calories) unless hepatic encephalopathy is present. Merck adds that keeping muscle on the dog matters.

Where sources differ: VCA's owner page on liver diets says the protein in a recommended food "may be lower" than in typical dog food, without tying that to hepatic encephalopathy. The professional references, Merck and JAAHA, are more specific, so that's what we go by here. Either way, your vet decides. Please don't cut protein yourself.

What else matters in a liver diet?

Fat usually doesn't need cutting. Merck says fat generally doesn't need restricting in liver disease, with exceptions such as a long-term blocked bile duct, or a gallbladder mucocele (a gallbladder packed with thick, gel-like bile), where high-fat diets are a problem.
Some dogs need a fat ceiling. JAAHA says to avoid diets above 40 grams of fat per 1,000 calories if the dog has a history of pancreatitis or is a breed prone to it, has high blood fats or severe bile flow problems, or is overweight.
Small, frequent meals. Merck describes an easily digested, tasty, calorie-dense diet fed often in small meals.
Keep the dog eating. VCA mentions lower fiber, appropriate sodium, clean water every day, and treating nausea so the dog doesn't learn to dislike its food.

What is copper storage disease?

Copper storage disease is when copper builds up in the liver and damages it. Vets may call it copper-associated hepatopathy. Merck says Bedlington Terriers have an inherited form, and it's also documented in Labrador Retrievers, West Highland White Terriers, Skye Terriers, Keeshonds, American Cocker Spaniels and Doberman Pinschers.

It's diagnosed with a liver biopsy that measures copper in the tissue. Treatment is a low-copper diet, sometimes with a medicine that pulls copper out of the body. JAAHA gives the copper limit for these dogs as below 5 mg per kg of food on a dry matter basis (1.25 mg per 1,000 calories). Merck says prescription liver diets are "the only diets reliably restricted in copper content," so this isn't something to match with a regular food off the shelf.

One more note from Merck: liver copper levels in dogs have risen over time, possibly because of changes in commercial diets and more easily absorbed copper sources, and researchers have asked whether dog food copper guidelines should be revisited. If your dog is one of the breeds above, it's a fair thing to raise with your vet.

What about liver supplements or home remedies?

Only if your vet prescribes them. The veterinary references do mention vitamin E, zinc and SAMe for certain liver problems, but vets choose them, and the dose, for a specific diagnosis. Merck notes that too much vitamin E can interfere with vitamin K, and that dogs with copper storage disease should probably not get vitamin C supplements. A supplement that helps one liver problem can be wrong for another.

Is there anything I should keep away from my dog?

Yes: xylitol. VCA warns that xylitol, a sweetener found in some sugar-free gum and candy, causes a life-threatening drop in blood sugar and liver failure in dogs. If your dog gets into anything with xylitol, go to your vet or an emergency clinic now, and call ahead on the way.

Words you might hear

ALT (alanine aminotransferase): an enzyme that leaks out when liver cells are damaged.
ALP (alkaline phosphatase): an enzyme linked to bile flow, also raised by growth, steroids and Cushing's disease.
GGT: another enzyme that points to bile flow problems.
Cholestasis: bile not flowing out of the liver normally.
Bile acids test: a blood test of how well the liver is working.
Hepatic encephalopathy (HE): confusion or other brain signs caused by toxins a sick liver can't clear.
Dry matter (DM): a way of comparing foods with the water taken out.
Biopsy: a small tissue sample looked at in a lab.

What should I ask my vet?

Which enzyme is high, ALT, ALP or both, and what does that suggest for my dog?
Could a medicine, my dog's age or another condition like Cushing's be the reason?
What's the next test, and when do we recheck?
Should I keep feeding the same food for now?
Does my dog need protein limited, or is there no sign of hepatic encephalopathy?
Is my dog's breed at risk for copper storage disease?
Does my dog need a prescription liver diet, and which one?
Are there any supplements you want my dog on, and at what dose?

Where to go from here

If your vet mentioned blood fats too, read what it means when the vet says my dog has high triglycerides. If pancreatitis came up, see what it means when the vet says my dog has pancreatitis. For the big picture on therapeutic foods, start with special diets for dogs and cats: what the food should look like.

Prescription diets need your vet's authorization, and we're happy to reach out to your vet for you. Our own trucks deliver free on each town's route day, Tuesday through Friday, with a $20 minimum. Find your day on our local delivery page, or call 732-938-4470. For a sit-down conversation about your pet's food, book a free 45-minute Personal Pet Consultant appointment.

Sources

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