Can Guinea Pigs Eat Onions?

Guinea pigs eat a wide variety of foods. They will eat everything you give them and this is quite risky because along with the long list of foods that guinea pigs can eat, comes another long list of foods that guinea pigs should not eat.

It may be tricky to know where to draw the line. What to give them and what not to give them.

Guinea pigs are small animals which makes them susceptible to poisoning from very little amounts of unsafe foods. Foods that are perfectly healthy for us can easily be fatal to the little pets.

This is why you should be extra careful with what you feed them. Guinea pigs have a delicate digestive system and you should ensure that any food you give them is safe for their consumption.

That brings us to the question of onions. Are onions on the list of ‘okay-foods’ or are they on the list of ‘no-no foods’? Let’s find out.

Can guinea pigs eat onions?

Guinea pigs cannot eat onions because onions are toxic to them. Onions contain disulfides that are poisonous to guinea pigs. Disulfides attack the red blood cells resulting in conditions like anaemia, kidney diseases, and low amounts of oxygen being circulated in guinea pig bodies. Onions also have high amounts of calcium and phosphorus that are harmful to guinea pigs.

Why you should not feed onions to guinea pigs?

Onions are part of allium plants. All allium plants from onions and garlic to leeks and chives are pure poison to guinea pigs.

Feeding your guinea pig onions will lead to:

Bladder and kidney stones

Onions are high in calcium. Calcium in small amounts is good for young guinea pigs as it aids in the development of strong bones.

The mineral is however not required by adult guinea pigs and in high amounts it becomes toxic. High calcium brings about the formation of kidney and bladder stones.

This leads to urination problems in guinea pigs where urinating becomes painful or blood appears in the urine.

Anaemia and lack of oxygen

Disulfides in onions result in the damage of red blood cells. Lack of red blood cells leads to insufficient oxygen circulation in body organs which can lead to their failure.

Anaemia may also be brought about and both these conditions could be fatal to guinea pigs if not treated in time.

Digestive problems

Onions contain sugars and fiber in high quantities which may present digestion issues to guinea pigs. Guinea pigs have a delicate digestive system and a combination of the two may lead to stomach upsets and loose stool.

What will happen if guinea pigs eat onions?

Guinea pigs will get poisoned if they eat onions and they will experience one, two, or more of the effects we just talked of above.

Signs of guinea pig poisoning are:

  • Eyes and nose discharge.
  • Increased drooling.
  • Upset stomach.
  • Diarrhoea.
  • Breathing difficulties.

How to avoid onion poisoning in guinea pigs

Onion poisoning can be avoided by taking the following measures:

Not feeding the onions

At this point, the first measure is self-explanatory. Avoid feeding onions to your pet.

Whether you have red onions, green onions, or even shallots, remember that onions are still onions and no matter the variety none is safe for your pet.

Do not cook, boil or soak them to try and make them less poisonous either because the onions will still retain their properties no matter the state they are in.

Just avoid feeding your guinea pig onions and look for other safer alternatives instead.

Keeping onions out of reach

Before letting your guinea pig out of their cage, make sure to keep onions and other allium plants out of reach, preferably locked up. Guinea pigs have a tendency of chewing on anything and everything they come across.

It would be so easy for them to get poisoned if they found onions left out carelessly and began chewing them. Your pet is your responsibility as they wouldn’t know what is poisonous and what is not.

Fence your garden

If you have a garden with onions or other plants poisonous to guinea pigs ensure that you fence it off to keep out your pet.

Your guinea pig could wander into the garden and munch on a good amount of poison if they stumble upon your onions and some tomato leaves.

A chicken wire would work just fine as the pet will not be able to go past it. Always ensure that you keep a keen eye on them whenever they are out.

Onion alternatives

Onions contain nutrients, antioxidants, fiber, and even Vitamin C which is a vital requirement for guinea pigs. However, the toxic nature of onions surpasses the good in them which is not worth putting your pet’s life in danger for.

Instead, you can feed them safe and nutritious alternatives like:

  • Bell peppers – they are high in Vitamin C, Vitamin A, fiber, and potassium, not to mention they are deliciously crunchy for guinea pigs.
  • Tomatoes – they are rich in fiber, Vitamin C, Vitamin K, and folate which aids in tissue growth. Feed only the tomato fruit and avoid other parts of the plant.
  • Asparagus – they contain Vitamin C, Vitamin K, Vitamin A, fiber, and minerals.
  • Lettuce – they have Vitamin C and vitamin A, with low amounts of calcium and oxalates.


Allium plants like onions are toxic to guinea pigs. Whether raw, cooked, boiled, or soaked in water, onions are poisonous to guinea pigs and shouldn’t be fed to them.

Feeding onions to guinea pigs brings about negative health impacts like urination problems, anaemia, digestion issues, and lack of oxygen in body organs.

In the case of food poisoning, always seek a vet immediately as onion complications could turn fatal.

Although onions are generally nutritious plants with good nutrients, antioxidants, vitamins, and fiber when it comes to guinea pigs you should opt for alternatives.

Nutrient-rich onion alternatives include bell peppers, tomatoes, lettuce, and asparagus.

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