Chronic Hepatitis and Copper in Dog Food
Liver copper in US dogs has risen since the 1980s, and specialists blame dog food. What copper hepatitis is, who gets it, and where the evidence is disputed.
Written by thecanineledger
This page carries no advertising, and nothing on it is for sale.
If your dog’s eyes or gums look yellow, its belly is swelling, its stools are black, or it seems confused or has a seizure: see a vet today. Confusion, collapse or seizures mean go now.
Our note: These signs come from the consensus statement. The urgency levels are ours.
A study of 546 dog livers tested at one US laboratory found that, in breeds known to be at risk of copper liver disease, the median liver copper level roughly doubled between 1982–1988 and 2009–2015. In other breeds it rose too, by more than half (Strickland et al., Journal of Veterinary Internal Medicine 2018). The authors concluded that “The frequent recognition of CAH in recent years is likely due to the observed increases”. CAH is copper-associated hepatitis.
While many specialists now believe commercial dog food is to blame, the evidence is not settled, and not everyone agrees. This page explains what copper hepatitis is, which dogs are at risk, and what each side of the argument has found.
1. What chronic hepatitis is
Chronic hepatitis is long-term inflammation of the liver. Over time it can scar the liver. The 2019 consensus statement from the American College of Veterinary Internal Medicine (ACVIM) says “Cirrhosis reflects end‐stage CH”, where CH is chronic hepatitis (Webster et al., Journal of Veterinary Internal Medicine 2019).
It is often silent for a long time. The statement says it “seemingly has a long subclinical phase”. Up to 20% of affected dogs have raised liver enzymes on a blood test without being ill.
Early signs are vague. “Clinical signs typically are nonspecific, such as loss of appetite and lethargy.” In the studies the statement pooled, 61% of dogs had a poor appetite and 56% were lethargic. About a third were jaundiced, and about a third had fluid in the belly.
Copper is one cause. Copper builds up in the liver and damages it. The statement says every liver biopsy should be checked for copper, “as this is a common cause of liver injury and is treatable.”
2. Which dogs are at risk
The statement says copper-associated hepatitis “may develop in any breed, including mixed breeds”. It names these as predisposed:
- Bedlington Terrier
- Dalmatian
- Labrador Retriever
- Doberman Pinscher
- West Highland White Terrier
Genes matter, but don’t explain it all. In Bedlington Terriers, a gene test is useful. For Labradors, the statement says “there is yet not enough information to make specific recommendations on the use of genetic tests”. The Strickland study notes that gene variants found in Labradors “accounted for only 12% of total heritability.”
→ Choosing a Breed or a Mix: The Health Data Breeders Don’t Lead With
3. The case against dog food
The timing. The ACVIM statement says the rise in chronic hepatitis cases “beginning in the late 1990s correlates with the change in the premixes used to supplement Cu in commercial dog foods”. Cu is copper. The newer forms of copper are absorbed much better than the old one.
No upper limit. The statement notes that US feed guidelines set a minimum copper level for adult dog food “with no maximum limit”. It says “many commercial foods have Cu concentrations that far exceed the NRC recommendations by 2‐4 times or even more.” The NRC is the US National Research Council.
The panel’s view. “The panel believes” that the feeding guidelines, together with the more absorbable copper, “are linked with an increased prevalence of hepatic Cu accumulation in dogs”.
The coyote comparison. A 2026 study compared the livers of 104 older pet dogs with those of 88 wild coyotes. The dogs’ median liver copper was about ten times higher. The authors said this “corroborates concern regarding higher dietary Cu intake in dogs fed commercial dog foods” (Center et al., Journal of the American Veterinary Medical Association 2026, abstract). They added that the findings didn’t show whether the coyote level is ideal for dogs.
Our note: The main sources are US-based. One says Europe’s copper practices differ slightly.
4. The other side
A feeding colony study. A 2025 study by researchers at a pet food manufacturer looked at the livers of 296 dogs in its own feeding colony, which died between 2006 and 2022. Liver copper rose slowly over time, but the authors said it “remained within the normal reference range” (Amundson et al., Journal of the American Veterinary Medical Association 2025, abstract).
Causation isn’t proven. Even Strickland’s team wrote that “causation cannot be determined”, though they called the timing “concerning”. That study also lacked diet histories.
What this means. No one has run a trial feeding dogs different copper levels over a lifetime. The argument rests on trends, comparisons and expert opinion.
Our note: The manufacturer study’s authors work for a pet food company, and an earlier 2024 paper by the same authors was retracted. We haven’t read the retraction notice in full.
5. Diagnosis and treatment
A biopsy is needed. “A definitive diagnosis of CuCH in all breeds requires a liver biopsy and copper (Cu) quantitation.” CuCH is copper-associated chronic hepatitis. Needle aspirates “have no role in the definitive diagnosis”.
A normal scan doesn’t rule it out. The statement says a normal ultrasound “should not dissuade the clinician from hepatic biopsy” in a dog with suspected chronic hepatitis.
Treatment. “Treatment for CuCH involves lifelong dietary Cu restriction and removal of Cu from the liver.” Removal uses a medication that binds copper. Diet alone isn’t enough: “Dietary Cu restriction does not replace the need for Cu chelation.”
Don’t change the diet on your own. If your vet suspects copper, they’ll recommend a specific low-copper diet. The statement says a homemade version is best formulated by a clinical nutritionist; look for a board-certified veterinary nutritionist, DACVIM (Nutrition).
Our note: We haven’t named the copper-binding drug, the low-copper diets, or any copper levels in food. Ask your vet about food if your dog is a predisposed breed.
→ Homemade Dog Food, Done Right: What the Evidence Actually Says · → How to Read a Dog Food Label
6. What we could not verify
| Commonly said | What we found |
|---|---|
| “Dog food is poisoning dogs with copper” | Unproven. Specialists are concerned, and liver copper has risen, but no trial has shown cause. |
| “Only certain breeds get copper hepatitis” | No. Some breeds are predisposed, but it can occur in any breed, including mixes. |
| “A gene test will tell me if my Labrador is at risk” | Not reliably. The known variants explain only a small part of the risk. |
| “Normal blood tests mean a healthy liver” | Not always. Liver disease can be silent for a long time, and blood tests miss early disease. |
| “A low-copper diet is enough treatment” | No. The consensus says diet doesn’t replace removing copper from the liver. |
Sources
- Webster CRL, Center SA, Cullen JM, et al. ACVIM consensus statement on the diagnosis and treatment of chronic hepatitis in dogs. J Vet Intern Med 2019: expert consensus
- Strickland JM, Buchweitz JP, Smedley RC, et al. Hepatic copper concentrations in 546 dogs (1982–2015). J Vet Intern Med 2018: retrospective study, one US laboratory
- Center SA, VanVranken P, Randolph JF, et al. Significantly higher hepatic copper concentrations in dogs compared to coyotes implicate excessive copper in most commercial dog foods. J Am Vet Med Assoc 2026. ⚠️ abstract read. Comparative study, 104 dogs and 88 coyotes
- Amundson MD, Motsinger LA, Brejda J, Hancock L. Retrospective analysis of hepatic copper concentrations in an internal feeding colony of dogs fed a broad range of foods. J Am Vet Med Assoc 2025. ⚠️ abstract read. 296 colony dogs. Authors employed by a pet food manufacturer
Always confirm with your vet before acting on anything on this page.