September 22, 2023
You might be thinking of feeding your cavies onions as a treat.Can Guinea Pigs Eat Onions?

Can Guinea Pigs Eat Onions?

You might be thinking of feeding your cavies onions as a treat. But can guinea pigs eat onions?

The simple and only answer is no, your guinea pigs cannot eat onions. Onions are highly toxic and eventually lead to anemia, digestive issues, and possibly death.

So, why shouldn’t you feed onions to cavies? Are there any special conditions in which you can feed them onions? And what about different types of onions?

We will answer all this and more in our ultimate guide on feeding onions to guinea pigs.

Why Are Onions Healthy For A Guinea Pig? 

Onions are not considered safe for guinea pigs. And you should take extreme precautions when feeding your guinea pigs onions. Onions are a good source of Vitamin C. But there are better sources than that. Keep in mind that even the smallest doses of onions are poisonous for cavies.

Onions are high in Vitamin C. Guinea pigs naturally do not produce their own V vitamin C, which means they rely on external sources. Hence, onions, in theory, could be a suitable source of Vitamin C.

However, this benefit should not encourage you to feed onions to guinea pigs. Instead, opt for healthier fruits like green peppers. Feed them fruits and veggies that are not high in sugar and will fulfill your cavies’ Vitamin C needs. You could also opt for Vitamin C-fortified pellets.

Nutritional Facts Of Onions:

Raw onions have very low calories and only provide 40 calories for every 100 grams (3.5 ounces). By fresh weight, onions are mostly made of water, with up to 89% of the onion being made from water. The rest is 9% carbs, 1.7% fiber, and some proteins and fats.

Raw onions are made of:

  • 89% water.
  • 1 grams of protein.
  • 3 grams carbs.
  • 7 grams fiber.
  • 2 grams sugar.
  • 1 grams fat.
  • 40 calories.

In addition to that, onions are also rich in:

What Should Be The Serving Size Of Onions To Guinea Pigs? 

You should not, under any circumstance, feed onions to guinea pigs. Hence, there is no recommended serving size. Even the smallest amount of onion can be fatal to your precious cavy.

Hence, it is recommended never to feed your cavy onions. But what if your cavity accidentally eats them? Then you should take them to the vet immediately. Do not wait around for symptoms of poisoning to appear. The more you wait, the more the onion could be damaging the guinea pig’s body.

How Often Should You Feed Onions To Your Guinea Pigs?

You should never feed onions to guinea pigs. This is because onions are very high in poisonous disulfides and excess calcium. They cause urinary and digestive problems and provide little to nothing nutrition to your cavy.

Onions can also lead to anemia, which is extremely harmful and can eventually lead to death. The first signs of onion poisoning in a cavy are liquid discharge from the nose and eyes. This may also be accompanied by vomiting as well as increased salivation.

If you fear that your guinea pig has eaten an onion, do not wait; call your vet immediately for instructions. They will guide you in administering first-aid and may urge you to visit a local clinic as soon as possible.

How To Give A Guinea Pig Onions:

You should not give your guinea pig onions. Consider alternatives if you want to get the same nutrients in onions without the harmful consequences.

Instead of onions, try feeding your guinea pigs:

  • Lettuce in small controlled doses.
  • Green peppers.
  • Leafy green vegetables.
  • Vitamin C-fortified pellets.

These are all great sources of Vitamin C and other important nutrients.

Are Onions Bad For Guinea Pigs?

Yes, onions are very poisonous and can lead to severe anemia and even death in guinea pigs. Here’s what feeding onions to guinea pigs, even the tiniest amount, can do:

Urinary Problems:

Onions can cause kidney stones due to the excess calcium present in them.

Digestive Issues:

Since onions contain a lot of excess calcium and starch, they can easily upset the cavy’s stomach.

Imbalance Of Phosphorus And Calcium:

Both calcium and phosphorus are toxic to guinea pigs. And in the wrong ratio, they can be even deadlier.


Since onions contain disulfides, they damage or destroy the red blood cells. This can lead to anemia, which will eventually cause respiratory issues and death.


If the symptoms of onion poisoning are not treated, they can lead to death. Do not wait for the symptoms to appear; rush your cavy to the vet if you fear onion poisoning.

Can Onions Kill Guinea Pigs?

Yes, onions can be fatal to guinea pigs. This is because onions can lead to severe anemia. If left untreated, this condition can easily lead to death in the guinea pigs. The toxic disulfides cause anemia in the onions that damage the red blood cells. Additionally, these cause respiratory problems.

Onions also create urinary issues such as kidney stones, which are not only painful but deadly. This vegetable also causes severe digestive problems due to the imbalance of calcium and phosphorus.

What Breeds Of Guinea Pig Are Allergic To Onions?

All breeds of guinea pigs get severe health issues from eating onions. Do not mistake guessing which breeds can or cannot eat onions. Onions contain a high amount of disulfides, damaging red blood cells. Hence, all breeds of guinea pigs are prone to anemia from eating onions.

Additionally, the phosphorus-calcium ratio is not suitable for guinea pigs. It causes kidney stones and other urinary problems, which can be deadly. And the starch content in the onions only upsets your cavy’s stomach and can be deadly.

Can Guinea Pigs Eat Green Onions?

Guinea pigs can only eat the green leafy part of green onions, and that too in moderation. Guinea pigs should not be fed the bulb part of green onions as it is equivalent to feeding them a raw onion. It is best to avoid this altogether and opt for other safer leafy greens like kale.

How Many Onions Can A Guinea Pig Eat In A Day?

Guinea pigs should not be fed onions under any circumstances. Even the smallest dose of onions can prove to be fatal. Contact a vet immediately if you notice your guinea pig showing signs of poisoning (hypersalivation, watery eyes, nose, etc.).


Are Baked Onions Safe For Guinea Pigs?

Cooking the onions won’t make them any safer for your guinea pigs. Cooked onions retain the toxicity of their raw counterparts. Frozen onions are also not good for cavies.

Can Guinea Pigs Eat Red Onion?

You shouldn’t feed your guinea pigs red onions as they are just as toxic as raw onions.

What To Do If Your Guinea Pigs Eat Too Many Onions?

Contact your vet immediately if you are certain that your guinea pig has eaten onions. They will advise you on first aid and how to safely get your cavy to the clinic.


So, can guinea pigs eat onions? The answer is no. Guinea pigs should never be given onions, not even in small doses. This is because onions can cause anaemia, indigestion, urinary problems, and even death.

Avoid feeding them onions and other variants such as green onions. Contact your vet immediately if you fear that your cavy has eaten onions.



Leave a Reply

Your email address will not be published. Required fields are marked *