FDA Warning Letters to Pet Supplement Companies Are Increasing: What This Means for Litigation
- Dr. Nihan
- Mar 19
- 3 min read
Updated: Apr 4
FDA Is Cracking Down on Pet Supplement Companies
In April 2025, the FDA posted warning letters to four pet product companies in a single batch: CBD Dog Health, MycoDog, Bailey’s CBD, and HolistaPet. All four were cited for marketing unapproved new animal drugs — meaning their products made claims that classified them as drugs under the Federal Food, Drug, and Cosmetic Act, but none had obtained FDA approval.
This wasn’t an isolated event. In November 2024, FDA issued warning letters to Nutrition Strength, Veterinary Select Formula, Intermarket Industries, and Pet Essences. In late 2023, even Chewy received a warning letter related to products sold through its platform. The pace is clearly accelerating.
For attorneys, each of these warning letters represents a potential case, either defending the company or pursuing claims on behalf of consumers who purchased products that were never proven safe or effective.
Why Pet Supplements Get Classified as Unapproved Drugs
Here’s what trips up most pet supplement companies: the regulatory framework for animal supplements is fundamentally different from human supplements.
For human dietary supplements, companies can make structure/function claims (“supports joint health”) without FDA pre-approval. For animal products, this exemption does not exist. If a pet supplement label says “supports digestive health” or “reduces anxiety” or “strengthens immune function,” the FDA can classify that product as an unapproved new animal drug.
Many companies don’t realize this distinction until they receive a warning letter. And by then, they’ve potentially been selling an illegally marketed product for months or years, creating both regulatory liability and consumer harm exposure.
How FDA-CVM Enforcement Creates Litigation Opportunities
Warning letters create downstream litigation in several ways. Regulatory defense: the company needs counsel and, often, a regulatory science expert to help respond to the FDA and restructure its claims and labeling. Product liability: if consumers or their pets were harmed by an unapproved product, the warning letter becomes evidence that the manufacturer knew or should have known the product lacked required approvals. False advertising class actions: class action attorneys use warning letters as the factual predicate for consumer fraud claims, arguing the products were marketed with false or unsubstantiated claims. Insurance disputes: companies may seek coverage under product liability or professional liability policies, leading to coverage litigation.
The CBD and Mushroom Pet Product Enforcement Wave
CBD pet products represent the fastest-growing area of FDA-CVM enforcement. Despite widespread consumer adoption, FDA has not approved CBD for use in any animal products. Every pet CBD product making therapeutic claims is technically an unapproved drug.
The mushroom/functional supplement space is following the same trajectory. MycoDog’s April 2025 warning letter for mushroom-based products signals that FDA is expanding enforcement beyond CBD into the broader functional pet supplement category.
For attorneys monitoring this space, the enforcement wave is creating a surge in both defense work and plaintiff-side consumer claims.
What Attorneys Should Look for in a Regulatory Expert Witness
FDA-CVM enforcement cases require an expert who understands both the science and the regulatory framework. The expert should be able to evaluate the product’s formulation and ingredients, assess whether the marketing claims constitute drug claims under the FD&C Act, analyze the company’s regulatory compliance history, interpret the FDA warning letter in the context of agency enforcement patterns, and provide testimony on what a compliant company should have done differently.
This requires a combination of veterinary science, regulatory experience, and product development knowledge. A regulatory attorney alone can’t explain the science. A scientist alone can’t navigate the regulatory framework. The ideal expert bridges both.
Expert Witness for FDA Warning Letter Defense and Animal Health Regulatory Disputes
Dr. Nihan Marun is a veterinary microbiologist (DVM, PhD Microbiology) who has written regulatory dossiers for FDA-CVM, USDA, and AAFCO submissions. She has managed international regulatory filings across US, EU, and APAC markets, and has consulted on labeling compliance, claims substantiation, and product classification for companies across the animal health industry.
She is available for both plaintiff and defense engagements in FDA enforcement, AAFCO compliance, labeling disputes, and animal health product liability cases.
