Blue Buffalo Dog Food Class Action, Consumers Allege the Company Hid Heart Disease Risks From Dog Owners

Two dog owners have sued Blue Buffalo in federal court, alleging the pet food giant marketed its products as healthy while concealing known links to dilated cardiomyopathy — a serious, potentially fatal heart condition in dogs. The consumer class action, Walsh, et al. v. Blue Buffalo Co. Ltd., Case No. 1:25-cv-05808, is active in the U.S. District Court for the Northern District of Illinois. The case has since triggered a second, separate lawsuit — this one between two of Blue Buffalo’s own insurers fighting over who must cover the company’s mounting legal defense costs.

Field	Detail
Case Name (Consumer Suit)	Walsh, et al. v. Blue Buffalo Co. Ltd.
Court	U.S. District Court, Northern District of Illinois
Date Filed	2025
Defendant	Blue Buffalo Co. Ltd.
Lead Plaintiffs	Ryan Walsh and Diana Walsh
Alleged Violation	Deceptive marketing; failure to warn consumers of DCM heart disease risk
Products / Services Affected	Blue Buffalo dog food products, January 2022 through present
Geographic Scope	Nationwide
Settlement	None — active litigation
Claim Form Available	No
Insurance Dispute Case	Nationwide Agribusiness Insurance Co. v. Blue Buffalo Co. Ltd., et al., Case No. 3:26-cv-00328, U.S. District Court, District of Connecticut
Plaintiffs’ Attorneys	TBD

Why Dog Owners Started Questioning Blue Buffalo

Blue Buffalo built its brand on a simple promise: better ingredients, better health for your dog. Its products carry names like “Life Protection Formula” and “Wilderness” and have long been positioned — and priced — as a premium alternative to mass-market kibble. Millions of dog owners trusted that positioning.

Ryan Walsh and Diana Walsh filed their class action alleging Blue Buffalo engaged in deceptive marketing by promoting its dog food as healthy and safe while allegedly failing to disclose potential links to heart-related health problems in dogs. Their complaint targets products sold from January 2022 onward and seeks to represent every consumer in the country who bought Blue Buffalo food during that period.

The heart condition at the center of the lawsuit — dilated cardiomyopathy, or DCM — is not a minor ailment. DCM affects a dog’s heart muscle, causing it to enlarge. As the heart’s chambers dilate, pumping becomes increasingly difficult, valves may begin to leak, and fluid builds up in the chest and abdomen — often progressing to congestive heart failure. Caught early, it can sometimes be managed. Left undetected, it can be fatal.

What the Blue Buffalo Lawsuit Alleges

The complaint claims Blue Buffalo marketed and sold dog food products while failing to warn consumers that certain ingredients could increase the risk of adverse cardiac conditions in dogs, including dilated cardiomyopathy. The plaintiffs allege this was not a matter of scientific uncertainty on Blue Buffalo’s part — they argue the company knew or should have known about the risk and chose not to disclose it.

Plaintiffs claim they suffered financial losses from purchasing the products and may have also incurred additional expenses, including veterinary bills, prescription medications for their pets, and the cost of replacing the dog food with safer alternatives. The lawsuit frames these as direct, quantifiable harms flowing from what the complaint characterizes as deliberate concealment.

This case does not exist in isolation. The FDA began investigating a potential link between canine DCM and certain dog food formulas back in July 2018, specifically examining grain-free products whose main ingredients included high proportions of peas, lentils, legume seeds, or potatoes. Blue Buffalo was among 16 brands cited by the agency — the FDA received 31 DCM reports involving dogs fed Blue Buffalo products, the sixth highest number among the brands under investigation.

Related article: Eggland’s Best Class Action: Consumers Say “Free to Roam” Was a $2 Lie Per Carton

The Laws Blue Buffalo Allegedly Violated

• Deceptive trade practices and consumer fraud laws — Federal and state statutes prohibit companies from making materially misleading representations about their products. The complaint alleges Blue Buffalo’s “healthy” and “safe” marketing claims were false or misleading given the alleged undisclosed cardiac risk.
• Failure to warn — Companies that sell consumer products have a legal obligation to disclose known safety risks. The plaintiffs allege Blue Buffalo breached that duty by staying silent about the DCM connection.
• State consumer protection statutes — The class action seeks relief under applicable laws in multiple states, given the nationwide proposed class of purchasers.

Who the Blue Buffalo Lawsuit Covers

You may be affected if:

• You purchased Blue Buffalo dog food products for your own dog
• Your purchase occurred between January 2022 and the present
• You live anywhere in the United States — the proposed class is nationwide
• You incurred veterinary costs related to a dog diagnosed with DCM or cardiac symptoms after eating Blue Buffalo products

No action is required right now. Save any purchase records, receipts, vet bills, or order confirmation emails — these may matter significantly if a settlement is reached.

What Blue Buffalo and Its Insurers Are Saying

Blue Buffalo has not issued a detailed public statement in response to the Walsh lawsuit as of the time of publication. AllAboutLawyer.com will update this article when a company response becomes available.

What has surfaced, however, is a fierce dispute between Blue Buffalo’s own insurance carriers about who must pay to defend it. Nationwide Agribusiness Insurance filed its own lawsuit in Connecticut federal court seeking a court declaration that Blue Buffalo and co-insurer Hartford Accident & Indemnity Company are responsible for their proportional share of Blue Buffalo’s legal defense costs in the consumer class action.

According to Nationwide’s complaint, it agreed to defend Blue Buffalo in the underlying lawsuit but did so under a reservation of rights, arguing that some of the alleged injuries may have occurred outside the coverage periods of its policies — specifically policies issued between 2016 and 2018. In plain terms: Nationwide says it has been footing part of a legal bill it believes Hartford and Blue Buffalo itself should be sharing — and it wants a court to say so officially.

Nationwide also seeks reimbursement for attorney’s fees and other defense costs it claims should be paid by the other parties. The insurance coverage fight does not address whether Blue Buffalo’s dog food actually caused DCM in any dog — it is purely a dispute about money and contractual obligations between insurers.

What Happens Next in Both Cases

• Blue Buffalo will file a formal answer to the Walsh consumer complaint or move to dismiss on legal grounds
• If the case survives a motion to dismiss, both sides enter discovery — exchanging internal documents, communications, and any evidence related to what Blue Buffalo knew about DCM risks and when
• The Walsh plaintiffs will then seek class certification, asking the court to confirm this case can proceed on behalf of all affected dog food buyers nationwide — not just the two named plaintiffs
• Separately, the Connecticut court will work through the Nationwide v. Blue Buffalo insurance coverage dispute, which will determine how defense costs are split between the insurers regardless of what happens in the consumer case
• No trial date has been set in either matter; complex consumer class actions of this nature typically take several years to resolve

This page will be updated as both cases develop.

Key Dates in the Blue Buffalo Cases

Milestone	Date
Walsh Consumer Lawsuit Filed	2025
Nationwide Insurance Lawsuit Filed	March 5, 2026
Defendant Answer Due (Walsh)	TBD
Discovery Period	TBD
Class Certification Hearing	TBD
Trial Date	TBD
Settlement (if reached)	TBD

Frequently Asked Questions

Is the Blue Buffalo DCM lawsuit real?

Yes. The case — Walsh, et al. v. Blue Buffalo Co. Ltd., Case No. 1:25-cv-05808 — is on file in the U.S. District Court for the Northern District of Illinois. A second related case involving insurance coverage is separately active in Connecticut federal court.

Can I file a claim against Blue Buffalo right now?

No. The case is still in active litigation with no settlement reached. No claim form exists yet. If a settlement is approved in the future, a formal claims process will open for eligible dog food purchasers at that time.

Do I need a lawyer to join this lawsuit?

Not necessarily. If the court certifies a nationwide class, you may be automatically included as a class member without hiring your own attorney. You would only need separate legal representation if you want to pursue an individual claim outside the class action.

What should I do if my dog was diagnosed with DCM?

Consult your veterinarian immediately if you suspect cardiac symptoms — lethargy, difficulty breathing, reduced appetite, or a distended abdomen are common warning signs. Document everything: vet records, food purchase receipts, and product packaging. This documentation could be critical if a settlement is reached.

What is DCM and how serious is it in dogs?

DCM results in an enlarged heart. As the heart and its chambers become dilated, pumping becomes more difficult and heart valves may leak, leading to a buildup of fluids in the chest and abdomen. DCM often results in congestive heart failure. It can be managed with early veterinary intervention but can be fatal if undetected.

What happens if the Blue Buffalo case settles?

If the parties reach a settlement, class members who meet eligibility criteria will typically receive notice by mail or email and be given an opportunity to file a claim for compensation. The amount each person receives depends on the total settlement value and the number of valid claims submitted.

Will I be automatically notified if there’s a Blue Buffalo settlement?

Potentially — courts require public notice of class action settlements, and you may receive direct notification if your contact details are linked to a Blue Buffalo purchase. The safest approach is to monitor court docket updates or legal news sites that track consumer class action developments.

What role did the FDA play in investigating Blue Buffalo and DCM?

The FDA began investigating whether canine DCM could be linked to certain pet foods in July 2018, examining grain-free formulas whose main ingredients contained high proportions of peas, lentils, legume seeds, or potatoes. The agency acknowledged that the potential connection is a complex scientific issue that may involve multiple factors. The FDA’s investigation and its public naming of Blue Buffalo among the brands associated with DCM reports form part of the backdrop for the current consumer lawsuit.

Sources & References

• Walsh, et al. v. Blue Buffalo Co. Ltd., Case No. 1:25-cv-05808, U.S. District Court for the Northern District of Illinois — Justia Docket
• Nationwide Agribusiness Insurance Co. v. Blue Buffalo Co. Ltd., et al., Case No. 3:26-cv-00328, U.S. District Court for the District of Connecticut — Justia Docket
• FDA Investigation into DCM and Grain-Free Dog Food — fda.gov
• Petfood Industry, reporting on DCM litigation and FDA investigation

Last Updated: March 25, 2026.

Disclaimer: This article is for informational purposes only and does not constitute legal advice. Legal claims and outcomes depend on specific facts and applicable law. For advice regarding a particular situation, consult a qualified attorney.