10 Most Toxic Food for Pet Mice

Since pet mice are not picky eaters at all, you, as the owner need to take control of the situation. Your job is to make sure your little pet eats the healthiest foods possible. As a result, your pet mouse will thrive and live a long, happy and healthy life.

While it is good to know about the range of healthy foods that mice eat, what about the toxic ones? You might fall into the mistake of feeding them one of the most toxic foods as a treat. Unfortunately, this is common because some of the simplest and seemingly healthy foods can be toxic for them.

This is why we wrote this article, where we list all of the foods that mice should not eat. The foods listed below are all toxic and we are going to explain exactly why.


Chocolate is not the healthiest option for humans either and it is straight-up toxic for pet mice. It is not only bad for mice but for many other animals as well, including cats and dogs. Chocolate is actually so poisonous that it can cause foaming in the mouth if fed in big amounts.

It can slowly kill your pet mouse while causing diarrhea and seizures. In short, you should never feed it to your pet. The darker the chocolate, the bigger the danger of it causing serious health problems.


Candy contains an incredibly high amount of sugar, which is really bad for pet mice. They have a problem digesting foods that contain sugar and end up having diarrhea as a result. Not to mention that candy does not contain any valuable nutrients.

Even the treats you give to your mouse have to be somewhat healthy. A really small piece of candy would not do much harm, it just makes no sense to feed something to your pet that doesn’t contain any nutrition.


Cheese is something that is very hard to process for the digestive system of a pet mouse. Unfortunately, people still believe that cheese is good for mice. They have seen so many movies and cartoons where mice grab a piece of cheese and eat it as their favorite food.

This could not be farther from the truth, as it is not healthy for them at all. They might like the taste but cheese can cause serious digestive problems. There are various types of cheese that can be moldy as well. We consider those stinky cheeses as fancy food but for mice, it is toxic and very dangerous.

The thing is that most types of cheese are not even considered as tasty by pet mice. They are probably not going to touch it and even if they do, it will only cause a stomach ache for them.


Potato is one of those foods that is considered as a dangerous treat for pet mice. The only safe one you can prepare is sweet potato. You can cook it and then it becomes a pet mouse-friendly food. What makes it bad for pet mice is that raw sweet potato contains compounds that are potentially harmful.

Once the potato gets in the belly of your mouse, those compounds start to turn into cyanide, which is incredibly toxic. Potatoes are not particularly nutritious for mice anyway so it is not even worth to experiment with them.

Moreover, potato chips are completely out of the question because there is a lot of salt and artificial seasoning on them. Your pet mouse needs to eat something more natural.

Fruit Seeds

No matter which fruit you feed to your pet mouse, make sure to always remove the seeds. Those also contain some amount of cyanide. That amount can’t be harmful to us, but pet mice are much smaller and even a little of it can cause harm in their body.

There are also other seeds that contain a high amount of fat. Pumpkin seeds, for example, are high in fat and thus are hard for pet mice to digest. Mice often just naturally leave those seeds in the cage because they know it is not a good food source for them.

The two kind of seeds that are the most toxic to pet mice are definitely apple and pumpkin seeds.


Not all parts of the avocado are toxic but its pit and skin are for sure. You will not only need to remove the peel but also the flesh near the seed and peel. These slightly different in color, which makes them easier to remove.

Otherwise, the rest of the avocado is completely safe for them and a good source of nutrition. Just make sure not to feed them too much of it because avocado contains a lot of fat as well. And remember that there are plenty of other healthy mouse foods to choose from and avocado is not essential in their diet.

Grapes and Raisins

Raisins and grapes are poisonous to pet mice and they can even stop their kidney from functioning. It is best to completely leave these foods out of their diet. Unfortunately, many sources recommend grape as safe food for mice.

Grapes can be harmless if they are super fresh but it is better not to play the lottery here. There are many other foods that are completely safe for mice so you should feed them those instead. Researchers still haven’t found out exactly why raisins and grapes stop kidney function but the evidence is there that they do.

If you don’t want to worry about it, then it is better to skip grapes and raisins altogether.

Garlic and Onions

Garlic and onions are not only toxic to mice but they absolutely hate their scent. Therefore, they are not even going to eat either of these if you just leave them in their cage. In fact, they hate garlic so much that it is often used to make wild mice go away.

If you know there are wild mice in your house, put down some garlic in as many of their pathways as you can. Those mice are literally going to run away once they sense it.


Even though almonds contain arsenic, we can still eat them because it is such a low amount. If pet mice would eat it, however, that amount of arsenic would be toxic. In theory, you could help your mouse build up tolerance for arsenic but is it really worth trying?

There is a long list of healthy foods that don’t contain anything poisonous that you can feed to your pet instead. Not to mention that plenty of those foods are much cheaper than almonds. Your pet mouse is surely going to react badly to almonds, it is just not clear to which degree.

Coffee Beans

Coffee beans are well-known to be poisonous to a lot of animals. While it can help us to wake up at the morning, it is simply toxic to pet mice. It is better to make some good coffee than to give those beans to your pet.

We are huge compared to pet mice and this also means that even a tiny portion of coffee can kill your pet. A mouse doesn’t even weight a pound and in order to calculate how much harm coffee dan do, you need to take weight into account.

If you would go through these calculations, it would turn out that coffee is extremely toxic to mice.

Wrapping Up

It is important to keep your pet mouse on a diverse diet, which is why giving them occasional treats is a great idea. However, not everything that seems like a good treat is actually good. There are plenty of foods that are toxic to mice, including the 10 most toxic ones that we mentioned in this article.

If you have found something at home that seems like a good treat to give and not sure whether it is toxic or not, ask the Internet. It is better to be safe than sorry when it comes to pet mouse diet.

avatar Jane
Jane is an experienced animal care specialist with a focus on rodents and small mammals, with over 10 years of experience in the pet industry. Her articles provide practical guidance on choosing the right pet and managing common health issues. Jane is an advocate for animal welfare and supports organizations dedicated to protecting wildlife. read more...

Questions and Answers

The ironic thing is while reading this article I noticed I have given all of these things to my pet mice besides chocolate, candy and coffee. Lol.

One of my mice is a field mouse (grey Deer Mouse species) who I’ve raised from a baby since 2018 and the other is a one year old “fancy” mouse (pet shop variety)

I have given them french fries, swiss cheese, grapes, avacado, many almonds, human foods containing onions and spices, mint leaves, meats and even alcohol- yes, alcohol. (I gave Miko, my deer mouse, a wide bottle cap full of cider that he drank in a night 😳).
I’m not trying to say you’re wrong about all these ingredients. Things like chocolate I definitely would not give to a mouse. But a couple on the list like almonds and potatoes seem strange to me. Maybe ive damadged their health somehow but I can’t see any signs of it, especially in Miko who is as quick as lightning and usually happy to run around collecting things i give him.
But one things interesting about the grapes, is that both mice rarely have eaten more than half a grape and now they dont really want them anymore so i stopped feeding that to them. Fries they seem to love when i rarely give it to them. I dont understand how potatoes which are very starchey turn to some amount of cyanide in mice digestion.

In the end all I can say is unfortunately i have spoiled them to the point where they wont even eat store bought mouse food anymore. Miko literally throws it in his garbage pile 🤣

Yes he actually has an area in his big cage which he designated for rubbish. Deer mice are smart. 🙂

So I give my mice all sorts of different treats (some that were on this.list) and it hasn’t effected them, I make mini peanut butter and jelly sandwiches that are about the size of your thumbnail and they love them, I also make cucumber and turkey sandwiches, what can I say, they love them. Honestly, I want to give them a life of riches so 🤷, but their regular diet/snacks is oats, pumpkin seeds, yogurt drops, and bits of other stuff.

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