Can Cats Eat Mayo? Is Mayonnaise Safe for Cats?

Posted in: Cat Health - Last Updated: September 5, 2023 - Author: Mayurii Rajvanshi
Posted in Cat Health 
Last Updated: April 5, 2022  
Author:  Mayurii Rajvanshi
Can cats eat mayo

You’re probably binge-watching Netflix with chips and mayonnaise to keep you company. Suddenly, your cat walks into the room and wants its share. Can cats eat mayo? Is there any major concern here? 

The bigger question is, should you? 

There is no straightforward yes or no to this question.  We’ll decipher it bit by it. 

As with most human foods that you might allow your cat to taste, the question comes down to two things. Firstly, is this toxic to your cat? And, secondly, if it’s not immediately poisonous, is it unhealthy for your cat?

Can Cats Eat Mayo?

Although the usual main ingredients in mayonnaise are not toxic to cats, they should not be eating mayo in any amount other than a lick or two.

Mayo has the probability of making them fat simply because it has a high fat content.

It can also result in diarrhea and vomiting because of this amount of fat that your cat may find hard to digest. It is people's food not meant for cats.

That’s the verdict!

But what if your cat gets a lick or two of mayonnaise?

Well, it’s not the end of the world. It’s safe for your cat because it’s not poisonous to them.

Let’s look at the usual ingredients in mayonnaise to get a clearer picture of whether mayonnaise is safe for cats.

Is Mayo Bad For My Cat? Are the Ingredients Toxic?

Soybean Oil

The majority of mayo available in the market has oil as the main ingredient.

Especially soybean oil. It can upset your kitty’s stomach leading to vomiting and diarrhea because of its fat content. 

Moreover, it is high in calories, which is not good for your kitty.

Surplus calories can cause obesity resulting in several health problems like kidney troubles, heart diseases, liver ailments, and issues with the cat's joints.

Obesity also makes it difficult for your kitty to stay cool and breathe comfortably. An increase in weight also means there is more strain on your furry friend’s knees and joints. They’ll even find it difficult to clean themselves.

All in all, try not to feed them anything that could be fattening. 

This is obviously not an immediate danger but you should think about the long term implications of overfeeding your cat with any kind of high fat foods, especially human foods.


Besides soybean oil, eggs are another main ingredient in mayonnaise. Obviously, eggs are good for cats.

Eggs offer protein, taurine, amino acids, vitamins A, D, E, B12, Iron, and Riboflavin.  All of these nutrients are amazing for your kitty’s health. 

But there's one problem- the egg yolk! Mayonnaise also contains yolk, which is high in fat and cholesterol.

If given in a moderate amount, it is good for your furry friend, but a lot of it can quickly lead to obesity as well as life-threatening conditions like pancreatitis and heart diseases. 

Obesity is also directly responsible for hyperlipidemia- a condition characterized by problems with the nervous system, rough skin, and seizures.


Mayonnaise also contains salt. You’ll be surprised to know your furry mate tolerates sodium better than humans.

But too much of it is bad for their health. If your cat eats a lot of mayo, the overload of sodium can cause water retention. 

Too much sodium can also cause dehydration and heart problems in sensitive kitties. Not just this, eating a lot of salt makes cats drink water more.

This means they’ll be using the litter box a lot more frequently. 

Pet Poison Helpline issues a strict warning against giving salt to cats.

It lists common signs of salt poisoning to watch out for. These include:

  • Vomiting
  • Diarrhea
  • Lethargy
  • Excessive thirst and urination
  • Incoordination
  • Decreased appetite

In severe cases, seizures, tremors, coma, and even death are possible.

Can cats have mayo


Almost all major commercial mayonnaise brands contain sugar. Although, unlike salt, sugar isn’t toxic to cats.

But that doesn’t mean it is good either. Cats are obligate carnivores and that should be their diet. Not sweets, cakes, and sugar! 

Sugar is nothing but empty calories for cats, which can easily lead to weight gain. It is especially riskier for older cats as it increases their risk of getting hyperglycemia.

It is a condition characterized by obesity or weight loss, increased urination, and increased thirst. 

Giving your cat too much sugar can quickly lead to sugar diabetes, a condition also known as diabetes mellitus.

In this chronic disease, your kitty’s carbohydrate metabolism takes a hit causing blood glucose levels to become high. 

Diabetes in cats can lead to cataracts, depression, and dehydration. 

Another reason to not give mayo to your kitty is that they cannot pretty much taste the sweetness in it.

So there’s no reason to provide it to them!

Vinegar and Lemon Juice

Most commercial mayonnaise brands also contain vinegar and lemon juice. Well, vinegar is a natural cat repellant.

If your kitty detects it, chances are very high, it’s not going to eat it. So, that’s one less thing to worry about.

But lemon juice is dangerous to your fur baby. 

In fact, all citrus fruits are dangerous to your fur baby because they contain a specific compound called limonene.

This compound is so dangerous that it can even cause liver failure and sudden death! 

Other toxic effects of limonene include vomiting, diarrhea, low blood pressure, depression, and tremors.

You better avoid lemon juice at all costs. Even in small amounts. Not even a droplet!  

The same applies to any mayonnaise flavored with lemon or even using it as a significant ingredient.

Can cats eat mayonnaise


Several commercial mayonnaise brands contain mustard. It is not toxic to cats but may contain preservatives and other additives that can cause allergic reactions in your beloved kitty.

Although we say mustard isn’t toxic to cats, nonetheless it’s not like it’s healthy for them. 

Mustard seeds are harmful to your kitty if it ingests them. This can lead to a number of health concerns.

The additional ingredients that come along with mustard can be poisonous to your furry friend. 

See, the main problem is that mustard comes from mustard seeds. If your kitty licks a teeny tiny amount of it off your plate, chances are it’s going to be absolutely okay.

But when it eats a large amount, it becomes a cause for concern.

Mustard can give bouts of gastroenteritis, leading to heavy episodes of diarrhea and vomiting

When Is Mayonnaise OK For Cats?

If your cat is constipated or suffers from hairballs you might find that your vet actually suggests giving your cat just a little mayo mixed in with their food.

This works because the fat content can help in both cases. 

Just be careful to only give the amount that your vet suggests and take their advice on what brand to use or any ingredients to avoid.

It’s also possible that the particular ingredients in mayo might add some probiotic cultures to your cat’s gut health and thereby help with their digestion.

Again, only very small amounts would be needed and recommended.

When is Mayonnaise Bad For Cats?

The  main way that mayo is bad for cats is simply because of its high fat content.

Mayonnaise isn’t good for us humans long term when we eat too much of it simply because it’s low in nutritional value and high in calories and fat.

Eat too much and you’re not getting much benefit and you are laying down unhealthy fat.

The same goes for your kitty if you let them eat mayo regularly.

That means there simply isn’t a good reason to let your cat have mayo.

Whilst you can argue that cats can have mayo, it’s not natural and it’s not doing them any good.

Can Cats Eat Mayo: The Verdict

Your cat licked some mayo off your plate while you weren’t looking? So, what is the answer, can cats eat mayo?

Don’t worry! Your kitty will be fine. Just make sure you don’t make this a habit.

And, definitely don’t feed your kitty a store-bought mayo that has mustard, vinegar, and lemon juice in it. 

Instead, you can make cat-friendly mayo at home. A preservative-free homemade mayo would be the most healthy option for your kitty.

Remember to feed in moderation. You can skip adding sugar. It’s not like your cat would miss the taste!

About the author

Mayurii Rajvanshi takes pride in being a content ninja, who is an avid animal lover. She has fostered numerous cats and developed in-depth knowledge of feline facts so she can write about cat health and cat care to help dispel myths with authentic information. Her aim is to encourage responsible pet parenting and cat adoption.