The ASPCA estimates that nearly 70-80 million dogs and upwards of 96 million cats live in American homes.  With a canine population so large, it’s no wonder that the pet food industry is worth over $24 billion.

With so many dogs and cats relying on the pet food industry for nutritious meals, it might be all too easy to assume the pet food ingredients on the big name or “recommended” brands are high-quality.

However, there may be more lurking in Fido’s food than we think. Explore the ten most dangerous ingredients in pet food, and crack the code of interpreting ingredient labels on pet food.

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infographic 10 bad pet food ingredients

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Carrageenan is a common ingredient in dairy products, meats, baby formula, and – you guessed it – dog/puppy food. Carrageenan acts as a thickener and stabilizer in over 70% of canned dog foods in the market. Despite the fact it is sourced from red seaweed, carrageenan adds no nutritional value.

Why is it dangerous?

A 2009 study reported that carrageenan initiates inflammation in the intestines of animals.

The inflammation indisputably leads to polyps and eventually colorectal cancer.

The Cornucopia Institute echoes the dangers of carrageenan and reports that the inflammation caused by carrageenan is linked to several IBS cases in cats and dogs. Even food-grade carrageenan affects the digestive systems of pets.

Don’t be misled

Pet (and even human) foods labeled as organic potentitally still contain carrageenan, which makes searching for carageenan-free canned food difficult. Use dry food if necessary until you can locate a carrageenan-free wet version.


Monsanto manufactures ethoxycin as a preservative used to prevent the fat content of dog food from becoming rancid. Interestingly, this preservative is also used a pesticide in pear orchards.

Why is it dangerous?

While banned in the European Union, ethoxycin continues to cause health problems for pets in America.  Side effects from consuming ethoxycin include:

  • Liver damage
  • Kidney damage
  • Thyroid damage
  • Allergic reactions
  • Reproductive issues
  • Leukemia
  • Birth defects (if consumed while pregnant)
  • Cancerous tumors

What is an alternative?

Look for pet food labels that list naturox, a combination of tocopherols, rather than ethoxycin. Use hypoallergenic dog foods without this ingredient.


Manufacturers in the food and beauty industries incorporate BHT, butylated hydroxytoluene, as a safeguard against rancidificaiton.

Why is it dangerous?

In 2011, Chemico-biological Interactions published the results of a study conducted by the Pharmaceutical Department of the University of Colorado which showed that BHT directly led to inflammation in the lungs and increased tumor growth, particuarly in the liver.

In the study on mouse lungs, inflammation consistently led to cancer. BHT is also an allergen, skin irritant, and negatively affects the reproductive systems.

What is the alternative?

Choose a dog food that lists Vitamin E as a preservative instead of BHT.

Propylene glycol

Proplyene glycol, a preservative, is also included in canned dog food because it retains water, keeping the food moist.

Why is it dangerous?

The FDA prohibits the use of proplyene glycol in cat food because it damages red blood cells, yet it is still present in dog food. This preservative also causes intestinal blockage and lesions in the stomach.

What is the alternative?

Vitamin E, C, and flavinoids are natural antioxidants that will preserve the food without damaging your pet.

BHA (butylated hyroxyanisole)

Like ethoxycin, BHA is waxy solid used to keep the fat in pet food from turning rancid.

Why is it dangerous?

While the FDA contends that BHA is safe at low doses, the repetitous diet of dog food with BHA has a cumulative effect on the dog. The Office of Environmental Health Hazard Assessment of the state of California found that in lab studies, cancerous tumors consistently grew in the presence of BHA. BHA also halts the blood clotting process.

What is the alternative?

Purchase pet food that lists vitamin E as a perservative rather than BHA. 

Food dyes

Industrial food production plants include food dyes in recipes for aesthetics. For example, green food dye is added to make spinach-flavored kibble green while orange food dye mimics the orange hue of carrots. No nutritional value is gained from the dyes.

Why is it dangerous? 

Non-organic food dyes are chemically created, and it is these chemicals that cause problems for both dogs and humans alike. The number one complaint is hyperactivity. Consuming food dyed artificially also damages organs and increases the risk of cancer.

What is the alternative?

When scanning labels, look for food dyes that are naturally sourced. For example, beet juice is a natural substitute for Red Dye 40 while annatto is frequently used to replace artificial orange dyes.

Corn syrup / Corn

Corn (among other grains) is used as a filler in both cat and dog food while corn syrup sweetens the food, making it more palatable.

Why is it dangerous?

  • Corn: Cats and dogs tolerate grains, but meat should compromise the majority of pet food because cats and dogs are carnivores. Corn and grain byproducts become unhealthy additions because there is little quality control over these ingredients. Like the meat byproducts, the “corn” in pet food is not held to the same standards of human consumption and therefore can be moldy or otherwise inedible. The presence of mold creates mycotoxins, which is the number one cause of pet food recalls.
  • Corn syrup: Consuming food on a daily basis with corn syrup leads to weight gain and diabetes. Because so many foods contain corn syrup, it’ s no suprise that nearly one in 400-500 dogs are diabetic.

What is the alternative?

Be diligent about purchasing grain-free pet foods. Avoid foods and treats that contain corn syrup.


Rendered meat byproducts consist of waste products from the food industry. Livestock that died of disease or age, expired grocery store meats, and remnants left over from restaurants are three examples of waste products present in byproducts. Byproducts that do not specifically list which animal the waste came from is likely to contain beaks, bones, feet, or other organs from a mix of animal species.

Why is it dangerous?

Because pet food companies include diseased animals and condemned animal parts in byproducts, there is a high risk for toxic ingredients including:

  • Traces of the euthanasia drug
  • Fungus
  • Bacterial pathogens
  • Free radicals

What is an alternative?

Pet food manufacturers list byproducts as animal fat, blood meal, or meat and bone meal on the nutrition labels. Search for pet foods that clearly mark “No filler or animal byproducts.”


Xylitol, a sugar alcohol, is a commonly used sweetener in sugar-free products such as gum, candy, and toothpaste. Xylitol exists naturally in fruits and vegetables; however, xylitol extracted for use in food and oral health products is derived from corn cobs.

Why is it dangerous?

It is well known that xylitol caused hypoglycemia, low blood sugar, in dogs. However, a recent study by the ASPCA indicated that severe liver damage is associated with xylitol consumption.  Because xylitol is becoming more present in human foods and snacks, it is even easier for a dog to ingest xylitol. Never feed human desserts to your dog, especially if it may contain this sweetener.

What is the alternative?

Out of precaution, consider creating a xylitol-free home.


Like xylitol, sorbitol is a sugar alcohol extracted from corn (in this case, cornstarch). Sorbitol has also been prescribed for humans as a laxative or as an ingredient in a laxative.

Why is it dangerous?

Apart from causing diarrhea in dogs, sorbitol can cause dogs to enter into a vicious cycle of hyperactivity followed by exhaustion.

What is the alternative?

Avoid any pet foods with sorbitol listed as an ingredient. Be cautious of giving a dog any table scraps containing sorbitol.

How do you know if your dog has been affected by these ingredients?

If you suspect your dog has ingested any food containing these ingredients, keep a journal of any suspicious symptoms and contact your dog’s veterinarian. Symptoms to watch for include:

  • Increased thirst
  • Increased urination
  • Extreme fatigue and weakness
  • Swelling anywhere on the body
  • Jaundice
  • Indigestion
  • Stomach pain
It may be tempting to grab a bag of organic food, toss it in the cart, and never glance at the label.

While there are certainly more quality controls and guidelines governing what ingredients can be included in organic foods and treats, just because a product is labeled “organic” doesn’t mean that it is free from these harmful ingredients.

For instance, many organic products still contain carrageenan. Even more confusing is the “Made with Organic” label, which really means that only some ingredients are organic.

The bottom line: Decode the labels. The time and effort (and money) that you spend on the right pet food will be worth your dog’s health and happiness.


Sugar Alcohols