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Prescription and Veterinary Diets–Are They Medicine? Are They Worth the Added Cost?

by Don Hanson

Pet foods sold as “prescription” or “veterinary” diets are typically promoted as treating medical issues like skin allergies, kidney disease, cancer, and more. They usually are much more expensive than regular dog food. For example, an 18.7 lb. bag of one company’s kidney diet sells for $104, while a 15 lb. bag of its regular dog food costs $46, half the price of the “prescription” diet. These alleged medical diets are often sold by veterinarians or outlets that will only sell you the food if you provide a “prescription” from your veterinarian or one of their online veterinarians, who has never examined your pet. I’ve placed the word “prescription” in quotation marks because the company that uses it as part of its brand name has been charged with deceptive marketing practices, as noted below.

This is not the first time the validity and quality of veterinary and prescription diets have been challenged. On October 25, 2023, Tim Wall published an article on stating, 

Hill’s Science Diet is facing a class action lawsuit because their prescription diets are not legally required to be sold with a prescription. The lawsuit plaintiffs also claim that prescription diets do not contain any medicine to treat the conditions they are promoted to address and are more expensive and essentially the same as most over-the-counter pet food products. Furthermore, they argue that if these diets had medicinal benefits, they would have been required to go through the FDA’s approval process for a new animal drug, which they did not.

On June 12, 2019, television station WJLA aired an investigative report addressing prescription diets that made similar allegations. In that report, veterinarian Dr. Karen Becker states, 

There is no medicine in prescription pet foods. There’s nothing “prescription” in the food at all. There are no drugs; there’s no medicine; there’s no herb. “By prescription” means you have to buy it from your veterinarian. But the list of ingredients on the back of the food is usually not much different than regular pet food.

Becker explains that “Prescription Diet” is a marketing term trademarked by Hill’s, the maker of Science Diet. That trademark is the reason other “prescription” pet food manufacturers alternatively label their prescription products “therapeutic” or “veterinary” diets. The Mars candy company sells “veterinary” diets under the Royal Canin brand; the Nestlé candy company under the Pro Plan® Veterinary Diets brand; and General Mills under the BLUE Natural Veterinary Diet brand.

WJLA contracted with an independent laboratory, Ellipse Analytics, to test 125 of these “prescription” diets made by the four companies mentioned above. These results were compared to test results for 1,400 different formulas of pet food that were not “veterinary only products.” The lab’s tests were for contaminants like such heavy metals as mercury and arsenic, antibiotics, pesticides, and mycotoxins. WJLA reported,

Overall, prescription pet foods performed no better than their off-the-shelf counterparts. And in some cases, prescription brands performed worse. Our tests showed 40% of prescription pet foods contained pesticides, one of the highest incidence rates of any category the lab has tested. The lab also found glyphosate, the controversial weed killer that is the active ingredient in Roundup, in some of the products.

The manufacturers of these specialty diets make unfounded claims that they treat disease when their products contain no unique drug or ingredient; the products often contain harmful ingredients in higher percentages than non-specialty pet food; and these “special” foods usually cost twice as much. Even if these claims were true and the food was significantly less expensive, I would not feed it to my pet. There are better options.

Personally, I hope the lawsuit against Hill’s is successful and that Mars, Nestlé, and General Mills also face similar cases. Consumers need much more transparency in the pet food industry because if these companies lie to you about needing a prescription, what else are they failing to disclose? Minimally, we need to see independent peer-reviewed research and FDA approval for any commercial diet promoted as having therapeutic effects. Also, remember that there are veterinarians like Dr. Becker who understand that fresh, wholesome food is as essential for our pets as it is for us.

Don Hanson lives in Bangor, Maine, where he is the co-owner of the Green Acres Kennel Shop and the founder of, an online educational resource for people with dogs and cats. He is a professional canine behavior consultant (PCBC-A) accredited by the Pet Professional Accreditation Board (PPAB) and a Bach Foundation Registered Animal Practitioner (BFRAP). Don is a member of the Pet Professional Guild (PPG), serving on PPG’s board of directors and Steering Committee, and chairing PPG’s Advocacy Task Force. He is also a founding director of Pet Advocacy International (PIAI). In addition, Don produces and co-hosts The Woof Meow Show podcast.

The opinions in this article are those of Don Hanson.

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