Can Cats Eat Mayonnaise With Tuna? (They Can, the Half)

The short answer is: No, cats cannot eat mayonnaise with tuna. Mayonnaise contains ingredients that can be harmful to cats. Of course, a bit of taste now and then shouldn’t cause any harm. However, as much as possible, avoid feeding your cat mayonnaise with tuna, or mayonnaise on its own.

While it makes a big difference if the mayonnaise is homemade, it’s still not enough reason to feed it to your cat.

A homemade mayonnaise usually has eggs, oil, mustard, and lemon.

Let’s study each of the ingredients and see how it may affect cats.

Why is mayonnaise the main problem for cats in mayonnaise with tuna meal?


A homemade mayonnaise uses either only the yolk or together with the white.

While cooked eggs may not be toxic, the raw versions can be.

A mayo comes from hard mixing and not cooking. Thus, it contains a raw egg that may put your pet at risk.

Olive oil

Mayonnaise doesn’t necessarily need olive oil. It can be any kind of oil, as long as it’s a neutral one.

Olive oil can be suitable for felines, as regular consumption can create a soft and shiny coat.

Still, together with other ingredients in mayo, it is not enough reason for felines to eat.

It would be much better to mix olive oil in other food rather than give it through a mayo.


Mustard or mustard seed is often a significant ingredient to mayo. Despite its flavor, though, it contains toxic compounds that can cause severe gastroenteritis.

This problem usually comes in the form of persistent vomiting or diarrhea.

Thus, you can only imagine feeding your pet something that has mustard or mustard seed in it.


The acidity in lemon gives the mayo a wonderful flavor. However, this acidity can be harmful to your pet.

Further, the lemon’s citrusy character, both its taste and scent, is something a kitty dislikes.

Thus, most people use lemon scent to repel kitties from messing in a particular area.

Both the fruit and the leaves of lemon can be toxic.

Lemon isn’t a necessary ingredient. In other instances, people substitute lemon’s acidity with that of the vinegar.

However, like lemons, vinegar, and felines are not suitable for each other since the acidity of vinegar can repel them.

Even if diluted in water, vinegar is still strong enough to affect kitties. Thus, vinegar consumption, even if it’s just a small amount, can be harmful.

The mayonnaise available in markets are usually high in fat. Thus you should only feed it on rare occasions and small amounts as well.

Remember: Too much mayonnaise can fill the intestine of cats with fat, leading to diarrhea.

Further, there is mayonnaise containing large amounts of dairy. Be sure to avoid such products, as most felines are lactose-intolerant.

Feeding such kinds of mayo can lead to so many digestive issues.


Mixing mayonnaise with tuna doesn’t lessen its toxicity. Even if you tried mixing mayonnaise with tuna, the risk would remain.

At some point, tuna consumption can even cause harm as well.

Most tuna contains fat that felines don’t need. Further, the canned ones increase the risk of mercury poisoning.

Now, you may be wondering if they can eat tuna salad since that’s where tuna and mayo usually meet.

RelatedCan cats eat lemon pepper tuna?

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Can cats eat tuna salad?

grey tuna for cats

The same with the mixture of only the mayo and the tuna, the tuna salad contains other ingredients. What makes it worse is that these ingredients are also harmful to cats.

Aside from mayonnaise, tuna, and mustard, a tuna salad has:


Onions are special spices that add a distinct flavor to any salad. While bits of onion are satisfying for our palates, it’s toxic for our cats.

A small number of onions and other spices can be lethal. A single bite can produce hard symptoms and can put your pet’s life in danger.

Thus, it’s not a good thing to give your pet some tuna salad.


Celery, especially its leaves, are safe for our feline pets to eat. However, too much consumption of celery can also cause an upset stomach.

As carnivores, they cannot digest large amounts of the plant. That won’t be a problem in a salad, though.

Still, with mayo and onions, even the celery can be harmful.


Salt is a bad thing for felines, together with all kinds of seasoning.

Cats cannot take sodium well, and too much salt can damage its red blood cells, leading to anemia.

Thus, the only recommended usually comes unsalted, unseasoned, and unflavored.

In a tuna salad, almost all ingredients can harm your cat. A little taste may not cause any harm. Still, you should avoid giving it as a treat as much as possible.

You May Also ReadCan cats eat black pepper?

Can cats lick Mayo?

A few licks of mayo as a treat probably won’t cause any harm.

If you have some mayo to spare, let your cat lick a few times, but don’t go overboard with it.

Always treat mayo as something unhealthy. Give it other food that contains no harmful ingredients.

As long as you feed it in moderation, and only as a treat, you cannot go wrong.

What kind of tuna is OK for cats?

Although tuna should not be part of a cat’s diet, a tuna treat won’t harm your cat.

You can go for canned or fresh tuna. But, go for the tuna packed in water instead of oil.

Further, if you can find one with minimal to no flavor and seasoning, that will be much better.

Also, go for a chunk light tuna rather than albacore. It will lessen the risk of mercury poisoning for your pet cat.

Do you want to know if cats eat flour tortillas or feta cheese? Check it out!

Can cats eat a whole can of tuna?

Tuna isn’t appropriate in large servings. It’s much more preferable if cats eat tuna only in small servings and not a whole can.

You can mix it with cat food and other food that is safe. However, as much as possible, don’t let your pet eat a whole can of tuna.

Tuna treats should not exceed 10 percent of your cat’s daily calories. Going over that can risk your pet’s digestive health.

In Summary

Mayonnaise and tuna are the right combinations that give quite a satisfying treat for us. Still, that treat is only applicable for us, and not for our cats.

Indeed, it can be tempting to share the food we enjoy to our pet cats, especially if we have a lot to spare.

The creaminess of mayonnaise mixed with the richness of tuna is genuinely enjoying. But, it’s not reason enough to give a share to our feline pets.

A treat should be not only delightful but also safe.

Always consider this, and you’ll have a safe and fantastic time with your pet, free from any food problems.

Read about other fish:

  • Can cats eat canned sardines? Read here.
  • Can cats eat sardines in tomato sauce? Read here.


Homemade mayonnaise recipe

Image credits – Photos by Karlis Reimanis and Kate on Unsplash

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