• Guinea pigs are herbivores, which means they only eat plants and plant-based food.
  • In the wild, guinea pigs eat fresh grasses and wild plants.
  • It’s vitally important for guinea pigs to eat lots of fibre to keep their teeth short, and their guts moving.
  • Vitamin C is an important part of your guinea pigs’ diet because they can’t produce it themselves
  • If you need to change your guinea pigs’ diet, it’s important to do so slowly to prevent an upset stomach.

What should I feed my guinea pigs?

An infographic explaining that your guinea pigs' daily diet should consist of at least their own body size in grass and/or hay plus one teacup of fresh greens and a tablespoon of pellets per guinea pig, and that you should never feed them muesli style food

The best diet for your guinea pigs’ is one that mimics their natural diet as much as possible. Our vets’ recommend the following:

  • Hay/grass: At least 85 – 90% of your guinea pigs’ diet should be hay and grass
  • Fresh greens and veg: A teacup amount of fresh greens and veg, per guinea pig, per day – greens and veg high in vitamin C are especially good
  • Pellets: Each of your guinea pigs should have one tablespoon of grass-based pellets per day
  • Water: Your guinea pigs should always have access to clean, fresh drinking water

Hay and grass

A photo of two guinea pigs eating hay

Guinea pigs rely on the fibre in hay and grass to keep their teeth short and their digestive system moving. Hay and grass should make up 85 – 90% of your guinea pigs’ diet, and unlike pellets, you can’t overfeed it. Make sure your guinea pigs have constant access to good quality, fresh feeding hay – timothy hay is a great option, and if possible, fresh grass from the garden*. Large piles of fresh feeding hay will encourage your guinea pigs’ to eat the fibre they need, while also providing a great place for them to burrow and forage!

*If your guinea pig is new to fresh grass, introduce it slowly to avoid an upset tummy, and never feed mown grass, as this can make them poorly.

Fresh greens/vegetables

An infographic showing vegetables safe for a guinea pig to eat

Guinea pigs’ need fresh greens and vegetables every day to help them get enough vitamin C (they can’t produce it themselves). 

Our vets’ advise one teacup of greens and veg, per guinea pig, per day, which can be split into morning and evening feeds. Try to aim for a variety of 5 – 6 different greens (including some that are high in vitamin C), to ensure they have a good balance of nutrients. If your guinea pig is new to fresh veg and greens, introduce it slowly, and don’t give them more than the recommended daily allowance because it might cause an upset tummy.

There’s a huge variety of greens that are safe to feed to your guinea pigs – some higher in vitamin C than others. Take a look at our list below for ideas:

Safe vegetables

  • Artichoke leaves
  • Baby corn on cob
  • Bell Peppers – high in vitamin C
  • Beetroot
  • Carrot tops
  • Cauliflower leaves and stalks
  • Celery leaves
  • Chicory
  • Collard greens
  • Courgette (and flowers)
  • Green beans
  • Lettuce – Butterhead, Red leaf, Cos, Little Gem (not iceburg)
  • Parsnips
  • Pak Choi/Bok Choi
  • Peas – leaves and pods
  • Rocket
  • Savoy cabbage
  • Spring greens – high in vitamin C
  • Swiss chard
  • Tomato (not leaves/vine, as poisonous) – high in vitamin C
  • Watercress

Safe herbs

  • Basil
  • Coriander
  • Dill
  • Mint
  • Oregano
  • Rosemary
  • Sage
  • Thyme

Safe veg to be fed in moderation

  • Asparagus ) – high in vitamin C
  • Broccoli (too much can cause gas) – high in vitamin C
  • Brussel Sprouts (too much can cause gas)
  • Cabbage (dark green varieties)
  • Cucumber (too much can cause diarrhoea)
  • Kale – high in vitamin C
  • Parsley – high in vitamin C
  • Red cabbage
  • Romaine lettuce
  • Spinach – high in vitamin C

You can also offer a variety of fresh items foraged from your garden as part of their daily greens – for more information, read our advice below.


Our vets recommend one tablespoon of pellets per adult guinea pig each day. Make sure the pellets you choose are made specifically for guinea pigs and are a consistent shape and colour, so they don’t only pick out the bits they like best. Grass-based pellets are ideal. Pellets should always be fed alongside hay, grass and fresh food, and should never be the main part of your guinea pigs diet.

Never feed your guinea pigs a muesli style mix (brightly coloured pellets, with a mixture of seeds and flakes) – this type of food is high in sugar, low in fibre, and can cause dental problems, weight gain, and tummy issues.


If you want to give your guinea pigs something special, our vets’ recommend items foraged from the garden, vegetables and a variety of hay and grass. Fresh fruit is also a nice treat, but only in very small amounts because it’s high in sugar and can cause weight gain. Guinea pig safe fruits include:

  • Apple (not the pips because they’re poisonous)
  • Banana
  • Blueberry
  • Carrot
  • Cherry
  • Kiwi
  • Melon
  • Pear
  • Plum
  • Squash
  • Strawberry

Try to avoid the colourful guinea pig treats available in pet stores – they are often very high in sugar, and bad for your guinea pigs’ teeth and tummy. If you do want to give your guinea pigs a treat, reduce their pellets and fresh food a bit, so they’re not having too many calories.

Why is a healthy diet important for my guinea pigs?

A photo of two guinea pigs eating herbs

Your guinea pigs’ diet plays a vital role in keeping them healthy. Without the correct vitamins, minerals and lots of fibre, they are likely to develop problems with their tummy, teeth, and vitamin C levels:

  • Gut health: Guinea pigs rely on a high fibre diet to keep their guts healthy and moving. A lack of fibre in your guinea pigs’ diet can cause their guts to slow down, or even stop working completely (which is called ‘gut stasis’). The fibre in your guinea pigs’ diet comes from generous piles of fresh hay and/or grass.
  • Tooth health: Guinea pigs’ teeth grow constantly, so it’s important that they continuously chew fibre to wear them down. If their diet doesn’t contain enough hay and/or grass, their teeth are at risk of overgrowing, which causes painful spikes that prevent them from being able to eat.
  • Vitamin C: Just like us, guinea pigs are unable to produce vitamin C themselves, so they need to get it from their food. A lack of vitamin C can cause a condition called ‘scurvy’. A good way to make sure your guinea pig is getting enough vitamin C, is by feeding fresh greens that are high in it.


My guinea pigs are eating their poo – is this normal?

Yes, it’s completely normal! In fact, it’s an essential part of their digestion, as it allows them to get all the right nutrients from their food, helping to keep their guts healthy. Your guinea pigs will produce two types of poo:

  1. A soft, sticky pellet called ‘caecotrophs’: This is kind that they eat, often straight from their bottom – they should do so immediately, meaning you shouldn’t see them very often.
  2. A hard dry pellet: This is the result of your guinea pig eating the caecotroph and pooping it out again as a solid pellet. Your guinea pigs won’t eat their solid pellets.

Do I need to give my guinea pigs vitamin C supplements?

If you’re feeding your guinea pigs daily fresh greens high in vitamin C, you shouldn’t need to provide them with any additional supplements. If you’re worried about your guinea pigs’ vitamin C intake, speak to your vet for advice. Vitamin C water drops aren’t recommended, as they put some guinea pigs off drinking, and Vitamin C is weakened by sunlight.

Which vegetables are unsafe for guinea pigs?

Not all fruits and vegetables are safe for your guinea pigs to eat – some are poisonous, some cause an upset tummy, and some pose as a choking hazard. These include:

  • Potatoes & skin
  • Onion
  • Garlic
  • Mushrooms
  • Tomato vine and leaves (the fruit is safe to feed)
  • Avocado
  • Iceberg lettuce
  • Rhubarb and leaves
  • Chives
  • Seeds & nuts

If you suspect your guinea pigs have eaten something poisonous, speak to your vet for advice.

How do I change my guinea pigs’ food?

If want to make a change to your guinea pigs’ diet, it’s important to do so slowly over a period of 2 – 4 weeks. Changing it too quickly might cause a tummy upset and cause them to stop eating, which is very serious in guinea pigs.

Start by mixing a small amount of new food with their current food – each day, gradually increase the amount, alongside reducing their old food, until they have fully transitioned. Monitor for signs of a tummy upset, and slow the process down if you notice any problems. New fresh foods should also be introduced in this way to prevent tummy upsets.

Can I feed my guinea pigs natural plants and forage?

Yes! In the wild, guinea pigs would spend their days foraging through fresh grasses and wild plants. Pet guinea pigs can benefit from this too, by eating a variety of natural foraged plants as part of their fresh food. Some of these plants can be grown at home and others can be foraged.

If do you decide to forage for your guinea pigs, avoid areas where weed killers or pesticides are used, as well as high traffic areas that are busy with people and dogs. It’s extremely important that you’re able to identify all of the plants you grow and forage – many look similar and some are toxic for guinea pigs. Safe plants for foraging include:

  • Apple leaves and twigs
  • Bramble/blackberry leaves
  • Calendula (marigolds)
  • Chamomile
  • Chickweed
  • Cleavers
  • Clover
  • Dandelion (in small amounts – it can make them go to the toilet more often)
  • Herb Robert
  • Lavender
  • Mallow
  • Dried or dead nettles (avoid feeding them fresh, as they can sting) 
  • Plantain
  • Pear leaves and twigs
  • Rocket – wild
  • Sow thistle
  • Strawberry or raspberry leaves
  • Willow leaves and twigs
  • Yarrow

Can too much calcium in vegetables cause a problem for guinea pigs?

Yes, too much calcium can sometimes play a part in causing bladder stones in guinea pigs. However, a lack of it can cause tooth and bone problems. For most healthy guinea pigs, feeding the right amount of a variety of different vegetables and leaves will mean they get the right amount of calcium. If any of your guinea pigs have a medical condition that is affected by calcium, such as a urinary or bladder problem, speak to your vet for advice.

Why is my guinea pig always eating?

Guinea pigs are natural grazers, so you should expect to see them eating hay and/or grass day and night – the constant chewing keeps their teeth and gut healthy. If a guinea pig stops eating, they are at risk of developing a life threatening health problem, called gut stasis.

The best way to check whether your guinea pigs are eating properly is by weighing them regularly. Weight loss can be a sign of illness, and weight gain could be a sign you’re overfeeding fresh food or pellets. It’s essential to contact your vet if you’re worried that your guinea pig is eating less, or if you notice a significant change in their weight.

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