Knoji reviews products and up-and-coming brands we think you'll love. In certain cases, we may receive a commission from brands mentioned in our guides. Learn more.

Most pet foods tell you they are complete nutrition for your cat or dog. Indeed the standards for pet food nutritional requirements in many countries is quite low, so low in fact that some foods use Ingredients that would never be allowed into the human food chain. In truth many pet foods, and pet products such as flea and tick medications, contain dangerous ingredients. One of these ingredients is Ethoxyquin.

Ethoxyquin may, or may not, be on the label of the pet foods that it is used in. This is part of the problem, however it is used to preserve “by-products”, and legally is considered to be part of the by-product and as such many pet foods are not listing Ethoxyquin on the label. In other cases it is used to preserve animal fat, and as the manufacturer did not add the Ethoxyquin they do not have to list it, however they will be aware if it is in the fat they used or not, and as such foods that list ingredients as Human Grade Ingredients, will not contain Ethoxyquin.

Look at the Ingredient list!

Ethoxyquin is a chemical pesticide, in most countries it is not accepted to be used in human foods, and indeed there are many concerns regarding its use in cat and dog foods. It has been shown to cause death in fish, and has been speculated to be linked to health problems in cats and dogs, including liver problems, and cancer.

In 1997 the United States Food and Drug Administration Center for Veterinary Medicine launched a study. The results were never published or made public, however it did result in a request that pet foods reduce the use of Ethoxyquin from 150 parts per million to 75 ppm. (source – Wikipedia) This is 300 times higher than the permitted residue in beef or pork to be consumed by humans.

In 1956 an Interview took place between Monsanto (makers of Ethoxyquin) and Dr. Lehman of the US FDA, who said if pressed he would have to rule that Ethoxyquin is “harmful and deleterious” and that no amount of retesting would convince him otherwise. This was reported in the January/February issues of Natural Pet Magazine, 1994.

Indeed one study done by Monsanto saw 67 pups born during 5 years, of which 32 puppies died, an extremely high mortality rate. See Reference.

The Chemical Toxicology of Commercial Products lists Ethoxyquin as a 3 on a scale of on a scale of 1 to 6 where 6 is so toxic that fewer than 7 drops would be fatal. It indicates concerns about depression, convulsions, coma, death, skin, or liver damage.

Many sites list Ethoxyquin as a carcinogen, used commonly as a rubber preservative. Wendy Volhard and Kerry Brown, DMV, state in their book “The Holistic Guide to a Healthy Dog” that the addition of Ethoxyquin in dog foods caused a rise in reported incidence of sterility, deformities in pups, periodontal disease, precancerous lesions of the liver, kidney, and bladder, as well as vaccination failure, and an increase in cataracts.

Many American made cat and dog foods continue to use Ethoxyquin, including Hills Science Diet, Purina, Iams, Royal Canin, Nutro, and Eukanuba (and others). As a cheap preservative it is also commonly found in the less expensive cat and dog foods.

Ethoxyquin may also be used in some livestock feeds (but is highly regulated). Of course these animals are typically slaughtered before problems arise from continued eating of this food, but at least one concerned owner, Sibylle Faye, and her veterinarian, had concerns that her lovebird suffered problems and died from the results of eating food preserved with Ethoxyquin, as reported at the bottom of this link.

When we talk about the use of Ethoxyquin in livestock food, in the USA, it can be used as a grain preservative, but must not be used for longer than two years. So why is it allowed in pet food? Why is a dangerous chemical pesticide banned in human foods, restricted in livestock, but allowed in cat and dog food?

To find a good pet food one must be willing to read the ingredient list, avoid Ethoxyquin, or anything that could potentially be preserved with Ethoxyquin. Foods should be listed as containing Human Grade Ingredients Only. Vitamin E, (Tocopherols) is a safe, but expensive preservative. Be aware that BHT and BHA area also low quality preservatives also linked to many health problems, however they (by their nature) must be listed on an ingredient bag, where as Ethoxyquin can be hidden.

Related Reading about Dog Food and Cat Food

Is there Dog Meat in Dog Food?

Facts on Dog Food Ingredients and Dogs with Allergies

Is the Food Your Dog Likes Good Food for your Dog?

Is the Food Your Cat Likes Good Food for your Cat?