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What Ingredients Are Bad for Dogs and Cats? [2024 Guide] tips

What Ingredients Are Bad for Dogs and Cats? [2024 Guide]

Does your pet suffer from itchy skin, chronic ear infections, excessive gas, loose stools, vomiting, or just not eating? It may be time to take a look at their diet.

As pet parents, we always want what’s best for our furry friends. That includes giving them a well-balanced diet. Picking out the right recipe for your dog or cat can be tough: even the most seemingly natural pet foods can be full of filler ingredients and digestive irritants. That’s why it’s important to know right from the start what foods to look out for on pet food labels. 

We’ll cover what ingredients are traditionally bad for dogs and cats so you can keep your pets happy and healthy.


What Ingredients Are Bad for Dogs and Cats?

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Here are some common ingredients in cat and dog food that have been shown to cause digestive problems:

1. Excessive starches (green peas, beet pulp, potato, sweet potato, etc.)

Sometimes, we make the error of assuming that, if an ingredient is good for us, it must be good for our pets. The reality is, dogs and cats are natural carnivores that thrive on a high protein diet.

While humans can benefit from a variety of ingredients in our diet like green peas and sweet potatoes, the same cannot be said for pets. Excessive starches are common ingredients in pet food–but they’re not doing our pets any favors. These are filler ingredients that keep manufacturing costs down. They provide no health benefits to dogs and cats, and can often be digestive irritants.

Pet food companies may claim that peas, corn, and other similar ingredients are good for your pet, but they actually may be the culprit of your pet’s digestive problems, like constipation, diarrhea, or even food allergies. 

If your dog or cat is suffering from digestive upset or food allergies, be sure to check their food for the following ingredients that could be causing these issues:

  • Green Peas
  • Beet Pulp
  • Potato
  • Corn
  • Barley

2. Animal by-products, meat by-products, and grain by-products

Take a look at your pet food ingredients list. Do you see a protein source that ends in “by-product?” A significant number of pet food brands choose to use these products, rather than the true protein (i.e. meat by-product instead of a meat source itself) to keep costs low while maintaining a higher protein and calorie content. 

Look for animal proteins in the first three ingredients for the most beneficial source of protein and essential amino acids.

When the meat source is unspecified, it truly is unknown what your pet is consuming. This can be problematic when dealing with a food allergy. 

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If your dog or cat is experiencing food-related allergies, be conscientious of what protein source is in their food to determine if that’s the cause, and if there’s a better alternative for them.


3. Soy products (soybean meal, textured vegetable protein/TVP, isolated soy protein, etc.)

In recent years, soy products have been used more and more frequently in pet foods, including prescription diets. Soybean meal is the most common and is used often because it’s a cheap source of protein. Some manufacturers even state that soy is a good alternative protein source for pets with food allergies to meats like chicken or turkey. 

Despite their prevalence, soy products can actually be an allergen as well. For dogs and cats alike, it can cause allergic reactions such as skin rashes, itching, and hair loss in addition to stomach upset. This is an increasing trend among genetically modified products. 

Additionally, studies have recently emerged that have linked soy to gastric dilation volvulus (GDV), or bloating. GDV is a serious condition, where air accumulates in the stomach, causing the stomach to twist and restricting blood flow throughout an animal’s body. If not treated immediately, the risk of fatality is high. 

While the causes of GDV, as well as preventative steps, are still being researched, there are a few facts we know. According to the American Kennel Club, “foods containing soybean meal or having oils or fats in the first four ingredients increase the risk [of GDV] by fourfold.”

Although bloating is most common in large-breed dogs, it can develop in small dogs and even cats. If you’re concerned that your pet is experiencing bloating, make sure to contact your veterinarian immediately.


4. MSG, melamine, & other chemically altered proteins (hydrolyzed chicken, hydrolyzed soy protein isolate, etc.)

Hydrolyzed proteins are typically prescribed by veterinarians to minimize the food allergies pets may experience. It is also prescribed to dogs and cats that have been diagnosed with Irritable Bowel Syndrome (IBS). 

These foods are formulated through hydrolysis, a process in which water chemically breaks down protein into pieces that are so small that the immune system no longer reacts to them. So if a cat or dog has allergies to chicken, they may be given hydrolyzed chicken instead to see if that eliminates the reaction while ensuring they’re getting sufficient protein. Many veterinarians (and even pet parents themselves) report good results from hydrolyzed proteins - but that’s not always the case.

In many of the studies cited that link a reduction in food allergies or IBS to a hydrolyzed diet, they often had ties to the pet food manufacturers in the first place. Independent research, on the other hand, could not find such definitive results. 

In fact, a 2016 study completed by Masuda, Kenichi et al. found that anywhere from 20 to 50 percent of dogs fed hydrolyzed protein will still experience symptoms due to food hypersensitivity. The reality is that elimination of a food allergen is the most effective way to prevent a reaction. 

The best option for your dog or cat is to try different, single-meat recipes. Feeding them a novel protein (a protein that your pet has never eaten before), is a great place to start.

Attempting to feed your pet the same protein they’re allergic to, just in a different format, is ineffective at best, and can be detrimental to your pet in the long term. 

Instead, feed your dog or cat a novel protein such as rabbit cat food or limited ingredient dog food to see if that eliminates their stomach upset.

Explore limited ingredient dog food


5. Artificial preservatives, colors & flavors

Preservatives are formulated into nearly all pet food recipes to ensure they have a long shelf life. Preservatives aren’t inherently bad, it’s just a matter of which preservatives are being used. 

Natural preservatives, such as Vitamin C, Vitamin D, Mixed Tocopherols (Vitamin E family), and Rosemary Oil are perfectly safe antioxidants that naturally slow the rate of oxidation down to preserve a product. Though these are safe options, many pet food companies instead choose to use artificial preservatives because they are much cheaper to manufacture. 

Not all artificial preservatives are bad, but there are some to be wary of. Two infamous additives are butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) which have both been identified as possible carcinogens for pets. 

They’re cheap ways to guarantee the shelf life of a product and are used as a synthetic alternative to Vitamin C. Many manufacturers will claim that they are harmless, but studies have shown otherwise.

Ethoxyquin is another controversial additive used in pet foods. It has been banned in the European Union and Australia, but is still permitted by the FDA to be used in pet foods in the U.S. in small quantities. Ethoxyquin is commonly used in pesticides, and studies have linked it to certain forms of cancer. 

Fortunately, most pet food brands have removed it from their recipes due to the backlash from consumers. Still, it serves as an important reminder to be conscious of what preservatives are used in our pet foods, and to do our research before feeding our pets.


6. Added sugars or sweeteners

While pets, like humans, can enjoy naturally sweet treats like fruit, sugar can be toxic and unhealthy in large amounts. A sugar-heavy diet can cause digestive upset, tooth decay, obesity, and diabetes in pets, so avoid ingredients like brown sugar, powdered sugar, processed sugar, and cane sugar. 

Artificial sweeteners can also be dangerous for your pets. Xylitol, an added sugar used in things like human candies, is very poisonous to dogs. Some kinds of peanut butter contain xylitol, so make sure you check those labels! Theobromine, often used in low-sugar chocolate, is also toxic for dogs. 

If you like sharing your human treats with your pet, make sure you check the ingredients list and consult your veterinarian.


7. Certain fats

While fats are an essential part of your pet's nutrition–and too much “bad fat” doesn’t affect their cholesterol levels or their risk of heart attack or stroke quite as much as in humans–there are some high-fat foods they should not eat.

Fatty human foods can be dangerous to your pets. For example, hide trimmings can cause pancreatitis in both dogs and cats, a condition that can be life-threatening or lead to long-lasting health conditions. 

Although avocado fat is considered healthy for humans, the persin in avocados causes digestive upset for our furry friends.


8. Unnecessary thickeners

While some thickeners are safe in pet food, such as agar, a plant-based thickener, some thickeners in pet foods are unnecessary and may cause health problems. 

Carrageenan, for example, which is extracted from red seaweed, can cause stomach irritation and has been linked to cancer and insulin problems. 

It’s important to check the type of thickeners used by your pet food brand to avoid adding unnecessary and potentially harmful ingredients to your pet’s diet.


9. Corn syrup 

Corn is a common ingredient in pet food, but it can be dangerous when in the form of high fructose corn syrup. Humans may use it frequently to sweeten our own food and drinks, but just as too much of it can create health problems for us, so too is corn syrup a dangerous ingredient for our pets when consumed in excess. 

Too much sugar leads to gastrointestinal discomfort, weight gain, and eventual obesity, alongside the health conditions that often accompany obesity. And if your pet has diabetes already, the rapid blood sugar spike may be particularly dangerous.


10. Nitrates or nitrites 

Human foods like hot dogs, ham, and deli meats often contain nitrates or nitrites, preservatives that increase meat products’ shelf life. Some pet foods also include sodium nitrite as a preservative, but nitrates (or nitrites) in high doses can be dangerous for pets. 

High levels of nitrates or nitrites in animals can lead to nitrate poisoning, methemoglobinemia (or anemia), and cancer.


11. Too much salt 

Dog owners in particular need to pay attention to their pets’ salt intake. Dogs with high levels of salt intake may develop salt toxicity, which causes gastrointestinal issues (like vomiting and diarrhea), and if the condition isn’t treated, it may cause seizures and death. 

“Too much” depends on the size of your dog, so it’s best to talk to your vet about the salt in your pet’s diet.


Specific Ingredients to Avoid for Cats


Cats may be picky eaters, but that doesn’t necessarily mean they’ll choose foods that are best for them. That’s why we need to check pet foods to ensure they don’t have harmful ingredients. Check labels for any of the following:

1. Artificial colors

Some cat food brands use artificial colors to make the food more visually appealing, but coloring agents may be harmful and have been linked to serious health effects.


2. Artificial flavor

These flavors are often used to make plant-based foods more appealing to carnivorous cats. Know that some food brands use ingredient names that aren’t immediately obvious as artificial flavors, like animal digest or glandular meal.


3. Carrageenan

Some gravy-style wet cat foods use carrageenan as a thickening agent and emulsifier to create a smoother texture. The FDA has labeled it as safe, but more studies are needed; degraded carrageenan is known to cause inflammation, gastrointestinal ulceration, and other gut health issues, and some studies have shown that food-grade carrageenan may cause inflammation, as well.


4. Highly-refined grains

You don’t have to remove all grain from your cat’s diet. But you should check to make sure your cat food doesn’t include highly processed grains like wheat flour or ground corn, which have been refined to separate the nutrient-rich bran and germ and are often used as fillers. 


5. PFAS (also known as Teflon)

PFAS stands for per- and polyfluoroalkyl substances, which are used to slow fat oxidation, protect against moisture, and extend shelf life. They are considered “forever chemicals” by the Environmental Working Group (EWG), meaning they don’t break down in the environment and also stay in the body for years (possibly decades). They may contribute to infertility, kidney problems, and testicular cancer.


6. Soy products

Soy is one of the top ingredients used as fillers in lower-quality cat food because soybean meal and other soy products are inexpensive sources of protein. The isoflavones in soy can cause a range of health issues for cats, including thyroid conditions or hormone-related health issues, while the phytic acid in soy products may also cause a lack of nutrient absorption.


7. Sweeteners

Did you know cats only have 500 taste buds as opposed to humans’ 9,000? Since cats aren’t able to taste sweetness with those taste buds, sweeteners (including cane sugar and molasses) serve no purpose in their food. 

Too much highly-sweetened cat food may contribute to weight gain and obesity, which causes multiple health problems and shortens your beloved pets’ lifespan.


8. Synthetic preservatives

Natural preservatives are safe in pet foods, so if you see ingredients like tocopherols and rosemary extract, you’ve found a safe bet. But if you see synthetic preservatives like butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT), return that food to the shelf.

High doses of these chemicals have been linked to kidney and liver damage in cats and have been linked to allergic reactions.

Ethoxyquin is another chemical preservative to watch out for. It is technically FDA-approved for pet foods, but it was initially used as a pesticide and has been banned in Europe and Australia.


9. Meat by-products

Brands often don’t know what species of animal their meat by-products come from, and by-products are also considered an inferior form of protein for cats. The rendering process destroys (or changes) natural enzymes and proteins, and is generally low-quality. 

Look for brands that use higher-quality protein sources like chicken or salmon rather than meat by-products or meat concentrate.


Specific Ingredients to Avoid for Dogs


Many dogs are excited to get their paws on any food, but it’s important to make sure they’re eating food that gives them the nutrients they need and that doesn’t include ingredients that may affect your dog’s health and well-being. 

Here are some ingredients to avoid:


1. Synthetic preservatives

Like cat food, some dog foods, treats, and bones use synthetic preservatives like butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), Ethoxyquin, Nitrates/Nitrites, Propyl Gallate, Carrageenan, MSG, or Sodium Hexametaphosphate. They give the food a longer shelf life, but they’re also known carcinogens that may cause liver or kidney failure and other health issues.


2. Corn syrup or xylitol (sweeteners)

Dogs don’t particularly enjoy sweetened food, so sweeteners are unnecessary. On top of that, these ingredients can harm your dog’s health; their high glycemic index increases your dog's risk for diabetes. Xylitol, although used as a sweetener for human foods, is toxic to dogs and may cause fatal incidents of hypoglycemia (low blood sugar) or liver failure.


3. Food dyes

Artificial coloring increases your dog’s risk for diabetes. It’s better to use food with its own natural coloring!


4. Unspecified meat meal/meat by-products

Unspecified meat meal and other meat byproducts may increase the amount of protein in dog food, but they are made from animal scraps, and manufacturers often don’t know the origins of those scraps, which means it can be hard to anticipate the effect byproducts may have on your dog.


5. Unhealthy fats

Some unhealthy fats to avoid include rendered fats and vegetable oil. Rendered fats may be a source of toxins and a potential source of harmful bacteria or mold growth. And vegetable oil is both unnecessary and may trigger inflammation, particularly for dogs with arthritis.


6. Melamine

Used to increase the amount of protein, melamine may cause kidney failure if ingested in high amounts.


7. Propylene glycol

Propylene glycol may help manage moisture in semi-moist foods, but it can also be toxic in large amounts. It can trigger allergic reactions and cause skin, liver, and kidney damage. 


8. Unnecessary fillers

Fillers bulk up dog food, but they have little nutritional value. Such unnecessary fillers include wheat gluten, cellulose, and potatoes.


9. Gluten and certain grains for dogs with allergies

Most dogs can have grains in their diet, but some dogs may have allergies to grains like corn, wheat, soy, and gluten. 


10. Soy products

Soy can be used as a filler, but it’s not a nutrient-dense protein. The isoflavones, a type of estrogen, may cause health issues by affecting your dog’s endocrine system. It’s also a common allergen that may cause gas and bloating.


What Ingredients to Look For in Dog Food & Cat Food



Choosing nutritious food for your pets doesn’t just mean looking for ingredients to avoid; it’s just as important to look for specific foods that are healthy and contribute to their overall health and well-being.


Protein is an essential part of your pet’s diet, but many pet food brands pad their foods with unhealthy or unnecessary proteins. Meat, however, should be a primary ingredient - first on the label. Cats are carnivores, and although dogs can survive on plant-based diets, they won’t thrive. Meat can provide your pets with all the vitamins, minerals, and amino acids they need.


The key is to look for brands that specifically name the proteins they use. The ingredients should list beef, chicken, or other specific meats rather than generic “meat” or “poultry.”


Some fats are unnecessary or unhealthy, but healthy fats are an essential part of a nutritious diet. They promote healthy skin and coats, and they help prevent chronic inflammation, which can cause or accompany many diseases. 


Omega-3 fatty acids, one kind of healthy fat, are found in fish, chicken, flaxseed oil, olive oil, egg yolks, and more. If you want to buy products that guarantee there are enough fats to make a difference in your pet’s diet, look for a guaranteed analysis on the label.


Like humans, pets need dietary fiber for a well-rounded, healthy diet. Fiber helps regulate the digestive system, which helps maintain blood sugar levels. You can ensure your pet has the fiber they need by looking for ingredients like beet pulp, pumpkin, sweet potato, whole grains, and psyllium husk.

Vitamins & Minerals 

Your pets need certain vitamins and minerals for a healthy diet just like you. Aim for food that provides your pets with:


  1. Vitamin A for a healthy immune system and cell function. You can find vitamin A in liver, fish oil, and various fruits and vegetables.
  2. B Vitamins for metabolic health and a healthy nervous system. You can find them in meat, eggs, and whole grains.
  3. Vitamin D for bone health. Find vitamin D in fish and beef liver.
  4. Vitamin E for fat metabolism and to protect against oxidative damage. Find it in leafy greens, seeds, and some oils.
  5. Vitamin K for helping blood clot. Find in leafy greens and fish.
  6. Calcium and phosphorus for healthy bones and teeth. Find them in dairy (for dogs rather than cats), fish, and meat.
  7. Potassium for muscle function and nerve transmission. Find in many whole grains, fruits, and vegetables.
  8. Magnesium for vitamin absorption and protein protection. Find in leafy greens, nuts, and whole grains.
  9. Iron for the formation of red blood cells. Find in meat, which provides the highest quantities.

Cats specifically need the amino acid taurine, which, unlike dogs and humans, cats can’t synthesize from other amino acids. If cats don’t get taurine from their diet, the subsequent taurine deficiency can lead to heart disease, blindness, and other health issues. Make sure your cats get the taurine they need from meat, especially organ meats like heart and liver.


How to Make Sure Your Dog or Cat Is Eating the Right Ingredients

Making sure your pet is eating the right food might seem overwhelming at first, especially with so many ingredients to look for and avoid. To make things easier, focus on the following steps for finding the best food for your pet’s needs:


1. Carefully read cat and dog food nutrition labels 

Skip past the claims on the front of the label and turn right to the ingredients list and nutrition label. Make sure the brand you’re interested in doesn’t have any of the “Ingredients to Avoid,” and then look for major ingredients that provide the nutritional value your pet needs, such as clearly-identified meats, certain fruits and vegetables, and certain grains.


2. Learn about alternative diets for dogs

Sometimes, when our pets are suffering from troublesome symptoms, we turn to alternative diets, just as we might for ourselves. Alternative diets, such as grain-free or gluten-free diets, may help your pet achieve good overall health by identifying food intolerances

One such diet is a novel protein diet for dogs. This diet involves introducing your dog to a protein that they’ve never tried before (which is what makes it “novel”). Many dogs may not have been exposed to rabbit or pork, so those are good meats to start with. 

A novel protein diet can help you address food sensitivities or allergies to chicken or beef that your dog may have developed.

KOHA offers a line of novel protein foods for dogs, all of which are primarily meat-based meals with protein sources such as duck, rabbit, pork, or salmon.


Limited ingredient diets are another method for treating allergies. 

Limited ingredient dog foods have fewer ingredients than most other dog foods. But make sure you still check the label–sometimes even limited-ingredient dog foods have hidden ingredients that may cause problems for dogs with allergies!

KOHA offers a range of limited ingredient foods that contain 90% meat (in the form of novel proteins like salmon or duck), green mussels for joint health, and pumpkin for digestive support.

Learn more about the novel protein and limited ingredient diets for dogs!


3. Choose high-quality dog or cat food 

Another way to guarantee your pet’s diet is nutritious and free from problematic ingredients is to choose brands known for their high-quality dog or cat food. Many of these higher-quality brands value providing pet owners with healthy foods.

If you’re looking for a brand you can trust, KOHA focuses on providing quality pet foods that are safe for sensitive stomachs, free from unnecessary or “junky” fillers, and a proven hit with picky pets! 

Find healthy, pet-approved food today.


We know your pet’s health is important to you. To help you choose the best food for your furry family members, here are a few more questions to consider:

What foods are toxic to cats?

Some foods toxic to cats include:

  • Avocados
  • Onions and garlic
  • Raw eggs or meat
  • Chocolate
  • Caffeine
  • Alcohol
  • Milk and dairy products
  • Grapes
  • Raisins

What ingredients should I stay away from in cat food?

Some of the most common ingredients you should stay away from in cat food include animal by-products, unnecessary grains and fillers, artificial colors or flavors, unhealthy preservatives, added sugars, and rendered fats.

What is the most unhealthy food for cats?

Some of the most unhealthy foods for cats include:

  • Chocolate
  • Onions or garlic
  • Grapes or raisins
  • Alcohol or yeasted dough
  • Dairy products
  • Citrus
  • Raw potatoes
  • Fat trimmings
  • Excessive treats

What are toxic foods for dogs?

The following foods are all toxic for dogs:

  • Avocado
  • Cherries
  • Chocolate
  • Grapes and raisins
  • Tomatoes
  • Mushrooms
  • Onions and garlic
  • Rhubarb
  • Sugar-free candy and gum (specifically, xylitol, the sweetener used in such candies)
  • Peanut butter that contains xylitol
  • Flavored waters, which often use xylitol
  • Dairy products
  • Caffeine
  • Alcohol
  • Macadamia nuts
  • Uncooked yeasted doughs
  • Moldy food

What should the first three ingredients in dog food be?

When shopping for healthy food for your dog, look for products with the following listed as the first three ingredients:

  • High-quality protein like chicken, beef, fish, lamb, or other specified meat sources. Dogs need protein for muscle and tissue development, a healthy immune system, and healthy skin and nails!
  • Natural carbs like those from whole fruits and veggies.
  • Healthy fats from animal fats or plant-based oils.

Is chicken meal bad for dogs?

Chicken meal isn’t necessarily bad for dogs. If a product lists chicken meal by-product, you may want to avoid it due to the lack of oversight in regards to where meat by-products come from. But chicken meal on its own can provide lots of protein, amino acids, glucosamine (for healthy joints), and important minerals. 

So make sure you look for high-quality, trustworthy brands that list “chicken meal” rather than “chicken by-product” as one of the ingredients.

What ingredient is bad for dogs in peanut butter?

Some peanut butter brands contain xylitol, which is an artificial sweetener. This is the only ingredient in peanut butter that may be dangerous for dogs. Otherwise, peanut butter is a good source of protein, healthy fats, and important vitamins, so it can be a healthy treat. 

Make sure you look for brands without xylitol!

My Cat or Dog Eats One or More of These Ingredients…Now What?

If your pet has any of the above ingredients in their food–don’t panic! There’s still time to get them adjusted to a new diet. 

If you’re concerned about the quality of your dog or cat’s diet, check out KOHA’s pet food options. All of the recipes are high quality, filler-free, and high in meat protein. For especially sensitive stomachs, we recommend the Limited Ingredient Diet entrées for dogs and cats.

Before you switch your pet to a new food, make sure to transition, over the course of five or more days to avoid additional stomach upset. You’ll soon see the difference that a healthy diet can make.

Check out healthy, pet-approved meals at KOHA!









Grognet, D. J. (2022, March 14). Bloat (or GDV) in dogs - what it is and how it's treated. American Kennel Club. Retrieved August 24, 2022, from

Masuda, K., Sato, A., Tanaka, A., & Kumagai, A. (2020, February 18). Hydrolyzed diets may stimulate food-reactive lymphocytes in dogs. The Journal of veterinary medical science. Retrieved August 24, 2022, from

Juncker, J.-C. (2017, June 7). COMMISSION IMPLEMENTING REGULATION (EU) 2017/962 of 7 June 2017 suspending the authorisation of ethoxyquin as a feed additive for all animal species and categories. Europa. Retrieved August 24, 2022, from

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