Can Guinea Pigs Eat Onions? (Read This First!)

Can Guinea Pigs Eat Onions

In short, guinea pigs shouldn’t eat onion. Onions contain thiosulphate and disulfide, which is toxic to them.

Even a tiny bite of onion can cause anemia in guinea pigs, which is highly dangerous.

In fact, onions can even kill your guinea pig.

In this article, I’ll be discussing why guinea pigs shouldn’t eat onion, what makes onion toxic and the potential risks.

Can Guinea Pigs Eat Onions?

No, guinea pigs shouldn’t eat onions. They are highly toxic for pets, including guinea pigs.

While onions are great for us, they hardly have any nutritional benefit for guinea pigs.

Onion contains sulfuric acid, and even a small bite can cause discharge from the eyes and nose.

And the main culprit is disulfide, a substance that causes hemolytic anemia in guinea pigs. It’s a very dangerous condition; it damages the red blood cell, which means lack of oxygen to the body tissues.

Your guinea pig may experience weakness, vomiting, diarrhea, stomach pain, pale gum and unusually breathing.

The symptoms can take several days to develop depending on much onion your pet has eaten.

Onion poisoning could be lethal, so take your guinea pig to a vet immediately if you notice any of the above signs.

Is Onion Safe For Guinea Pigs?

No, onions aren’t safe for guinea pigs because of two compounds, thiosulphate and disulfide.

These are the main culprit that makes onion so toxic for guinea pigs. Ingesting even a tiny piece of onions can have dangerous health issues like urinary problems, digestive issues, anemia, and even death in some cases.

Is Onion Safe For Guinea Pigs

In addition, onions have an excess amount of sugar and calcium, which is not good for small pets like guinea pigs.

They are not good at digesting sugar, so excessive sugar can cause digestion problems and obesity.

And calcium too much calcium can lead to problems like bladder stones and other complications.

What Makes Onion Toxic For Guinea Pigs?

Onion, garlic, and chive, all of these belong to the Allium family.  

According to VCAHospitals, onion contains chemical compounds called disulfides and thiosulphates, which is toxic to dogs, cats and other animals, including guinea pigs.

Disulfides and thiosulphates can lead to hemolytic anemia, which is a dangerous condition.

Some of the most common signs are:

  • Weakness
  • Loss of appetites
  • Gastrointestinal upset
  • Vomiting
  • Rapid heart rate
  • Pale Gum

Red blood cells are essential; they supply oxygen throughout the body, but hemolytic anemia makes them fragile and causes them to burst.

When the red cells are destroyed, this causes internal bleeding and deprives cells and organs anywhere in the body, resulting in abnormal urination, vomiting, loss of appetite, and kidney damage.

Considerable Risk Of Feeding Onion

Onion is toxic for guinea pigs, and in some cases, it can even lead to life-threatening situations.

Not only that, whenever guinea pigs eat onion, the disulfide and thiosulphate can lead them to irritation in the eyes, mouth and runny nose.

Considerable Risk Of Feeding Onion

Also, sometimes, it can even cause excess salivation, breathing issues and rapture of red blood cells.

Now let’s see what other complications they might have to face after eating onions:


Onion can cause some severe complications.

The foremost sign that you might see in your guinea pig is vomiting. Guinea pigs are not like cats or dogs that simply vomit to handle the undigested food.

 If your guinea pig starts throwing, which is rare, it means there is something serious; in this case, you should take your pet to a vet without delay.

Urinary Problems:

Onions contain a good amount of calcium which could be problematic. Guinea pigs do not need a lot of calcium, and too much calcium can cause urinary problems such as bladder and kidney stones.

If you feed your guinea pig a balanced diet, they should be fine; however, if you see any sign of high calcium like gritty or sludgy white urine.

You should consult with an expert vet.

Digestive Issues:

Guinea pigs have a sensitive digestive system, and eating onion can cause issues in the digestive system.

Onions contain a good amount of sugar; while they don’t taste sweet, they do have a decent amount of sugar in them.

Guinea pigs are not good at digesting sugar. So, whenever guinea pig ingests excessive sugar, it leads to digestive issues, blood sugar spikes and other complications.

Causes Anemia:

Another side effect of onion is that it causes anemia, a life-threatening disease. 

Onion contains disulfides which is toxic for guinea pigs. Once your pet eats anything that has disulfides, it damages the red blood cell, which means the body lacks the number of red blood cells to carry sufficient oxygen throughout the body.

Some of the common signs of anemia could be a weakness, fatigue, dizziness, shortness of breath, pale gum etc.

So, if any of the above sign is seen, immediately take your pet to an expert vet.


Onion is so toxic for guinea pigs that if you do not take any action within time, it can even kill your guinea pig.

So, if you suspect your pet has nibbled on onion or related veggies, do not wait for the symptoms to appear, instead, take them to a vet immediately and before it’s too late.

Remember that even the tiniest bite of onion can sometimes be fatal. So act wisely and keep your pet safe.

What Happens If A Guinea Pig Eats Onions?

Once your guinea pig eats onion by chance, it will cause serious health problems.

First of all, the disulfide and thiosulphate compound present in onion will damage the red blood cell, eventually leading to weakness, fatigue, dizziness, and shortness of breath.

Like other animals, guinea pigs cannot vomit; their body and brain circuits aren’t designed to perform the reflex. So if they eat something toxic, it must pass through their digestive system, resulting; in blockage or choking, and sometimes can be fatal.

In addition, the disulfide and thiosulphates in onion are so toxic that even a small amount can trigger several health problems like eye irritation, nasal and mouth discharge, respiratory problem, breathing issue and digestive issues.

The symptoms of onion poisoning can take a few hours to appear.

So, if you suspect your guinea pig has ingested even a small amount of onion by chance, you should immediately take your pet to a vet.

How Much Onion Can A Guinea Pig Eat?

To be honest, not even a tiniest bite!

If something has even a 1% of chance making my guinea pig sick, I would never feed it to my pets.

Instead, I would opt for other excellent guinea pig treats that are filled with nutrients.

My Guinea Pig Ate Onion, What Should I Do?

First of all, do not panic and act smart. This is the time when you should behave wisely and not emotionally.

If your guinea pig has consumed a good amount of onion, it could be dangerous for them.

While a tiny amount of onion won’t probably kill your guinea pig, it can still cause several health problems.

Onion poisoning is severe and can cause anemia, a rare disease that can damage red blood cells.

Guinea pigs suffering from anemia may experience fatigue, breathing problems, excess salivation, headache and stomachs problem.

If any of the above signs are seen, you should immediately consult your vet for emergency treatment.

This could be fatal, so do not wait for the last movement, take action as soon as possible.

How To Stop Your Guinea Pig From Eating Onion?

Guinea pigs shouldn’t eat onions; they contain disulfide and thiosulphates. These compounds are highly toxic for guinea pigs.

While guinea pigs have an excellent sense of what should they eat and what to avoid, there are chances that they might have a bite or so by mistake. 

So, it’s your responsibility to keep these things out of your pet’s reach.

Here are a few tips:

1. The most obvious place where your guinea pig might find them is in the kitchen, so before letting your guinea pig roam, make sure the pantry door is closed, and there are no bags of onions lying on the floor of the kitchen.

2. Secondly, whenever you work with onions for cooking, salad etc., make sure that your pet is nowhere around; otherwise, they might want to nibble on some.

3. If you are a fan of gardening and have some onion bulbs in your yard, make sure you cover or protect them with something so your guinea pig can’t reach there while playing.

4. Lastly, it’s obvious that you should never feed onions or anything that came from the Allium family to your pet.

However, pet parents often forget to check the label and offer them some of the junk food they have.

So, be wise and try to avoid this mistake; otherwise, you might have to face some of the problems mentioned earlier.

Final Thoughts

Guinea pigs shouldn’t eat onion; even the smallest piece can harm your guinea pig. They contain disulfide, which is highly toxic for guinea pigs; they can cause a fatal disease called anemia.

If you use onions for cooking or have them in the backyard, you should remove any potted plants from their reach. 

And make sure that there is no open pantry or bag of onions lying on the kitchen floor.

Lastly, try not to leave your pet inside the home or outside unattended.

Onion poisoning is a serious condition which could be fatal if not taken immediate action. 

So, if your pet has accidently taken a bit of onion, you should immediately take them to a vet.

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