What Guinea Pigs Can Eat (Everything You Need to Know)

What do you know about what guinea pigs can eat? Not much? Some people picture guinea pigs nibbling on grass – day in, day out.  However, that barely scratches the surface of a guinea pig’s diet.

What guinea pigs can eat includes a dazzling assortment of hay, grasses, guinea pig food pellets, vegetables, and fruits – which can be found locally or grown in your kitchen or backyard.  It’s important to feed your guinea pigs the right type (and quantity) of foods to keep them healthy and happy. 

I did some online research and took a deep dive into some books.  There’s a lot of information about a guinea pig’s diet out there.  Keep reading to learn the juicy details about what guinea pigs can eat (or avoid) as well as how much and how often they should be fed.

Daily Delights in a Guinea Pig’s Diet: The Fit Four

Before we dive into The Fit Four, let’s take a moment to understand a few things about guinea pigs knowing a few facts.  For instance, guinea pigs:

  • Are herbivores.  Unlike some of their rodent cousins, guinea pigs only eat plants.
  • Can be picky eaters.  Some are very selective about what they eat. It’s part of your job as a pet parent to figure out what those preferences are.
  • Require a balanced diet.  A guinea pig balanced diet.  This diet should be  80% hay, 15% fresh vegetables (a few fruits) and 5% pellets are your cavy’s daily nutritional needs.
  • Need vitamin C.  Turns out guinea pigs don’t make their own Vitamin C-which is something they have in common with us.  So, we must make sure our piggie pals get plenty of vitamin C in their food.
  • Have different dietary needs. Amount of items might have to be adjusted according to your cavies age, environment, health, etc. When in doubt, always contact your guinea pig’s veterinarian.    
  • Are herbivores.  Unlike some of their rodent cousins, guinea pigs only eat plants.

All guinea pigs need the same five elements in their diet.  They include water, hay, fresh produce, and guinea pig pellets.

I call them the Fit Four.  Because it’s what a (healthy) guinea pig needs to stay trim and slim (guinea pig slim, that is).  

Let’s take a closer look at the Fit Four:

1. Water  

Guinea pigs need lots and lots and lots of fresh water.  Daily.  It helps with digesting the unlimited amount of hay that your piggie pal NEEDS to eat.

And filter it if you live in a hard water area. Not sure if you have hard water?  Use a simple test to see if you have hard water.  Water filters

Here are helpful tips to make sure that you cavies have all the water they need:

  • Use a dripper bottle for water.  Avoid using a bowl if possible.  They’re easily tipped over-or trashed by bedding and guinea pig poop.  You don’t want to leave the house for the day and come back to find that your cavies haven’t had water all day.  
  • Rinse and refill the water bottles each day.  When you do, make sure that the water is fresh and free from particles – like guinea pig backwash.  Ugh! 
  • Inspect the bottles for leaks and make sure it’s operational.  Look for nasty floaties and other debris that might be in the water bottle-they can make your little friend sick.
  • Have at least one water bottle per guinea pig.  If one of your guinea pigs is a water hog, you don’t want your other cavies getting parched. Making sure each cavy has a water bottle prevents this.

2. Hay  

An endless amount of hay is necessary. Not optional.  Grass-based hay is highly recommended for healthy adults.

Timothy, orchard, and meadow hay are very popular – considered to be the best types of grass-based hay for guinea pigs. 

There are two main reasons why hay is the most important food for guinea pigs:

  • Hay wears down the teeth when chewed.  Guinea pigs must chew constantly to keep their teeth (which never stop growing) from getting too long.  It’s one of the reasons why it seems like guinea pigs are always chewing.
  • Hay is high in fiber and minerals, but low in calories.  This means that large amounts of it can be consumed by your guinea pigs without weight, bloating, or gas issues popping up. 

Just make sure that you use a safe hay feeder to feed your piggies their hay and that you choose the best one for you and your little friends.

3. Guinea Pig Food Pellets  

Water.  Lots. Hay.  Endless. Pellets?  Ummmm, pump those breaks.

On average guinea pigs (health adults) should be given a ⅛  to ¼ cup of vitamin-C enriched, grass-based pellets.  Pregnant guinea pigs and youngsters (a year or longer) can be given alfalfa-based pellets-their stuffed with extra calories and calories that those two groups need.    

Those are the basics.  Now, let’s get a little more specific.  Here’s a little more guidance on purchasing and making sure that you have the best quality pellets for your little buddies:

  • Read the label. Pellets should be 18 to 20% protein, 3 to 4% fat, 13 to 16% fiber, and at least .02 to 0.5 ounce of Vitamin C for pound (1 to 3 g vitamin C per kg). All pellets should be high-quality; free of unnecessary additions like seeds (a choking hazard), oil, nuts, bran, corn, and artificial flavors and chemicals.
  • Make sure it’s fresh. Note the milling date on the pellet package to verify the shelf life of the product.  If the food is too old, then the vitamin C won’t be effective.  Scurvy city for your guinea pig. 
  • Preserve the freshness. Store it in an airtight container, in a cool, dark place.
  • Throw out spoiled pellets. Chuck pellets that are more than 90 days old from the milling date.  As soon as you crack open that bag, the vitamin C starts to degrade. Also, throw out leftover pellets in your cavy’s feeding bowl at the end of the day and replace with new ones.

4. Produce Fresh Produce for Your Guinea Pig 

There are literally dozens of fruits, vegetables, herbs, and grasses that your guinea pig can enjoy. But, it all boils down to that magical one cup.  But, what goes into that magical one cup of produce? 

In an never-ending effort to keep things super simple and easy, let’s consider two things that most experts agree on. The one cup of produce must include:

  1. Mostly green, leafy vegetables.
  2. A wide variety of produce

Every day your piggie pal should have a leafy vegetable high in Vitamin C and a herb stuffed with minerals and other piggie-friendly nutrients.  Lots of variety, but not too much of anything. 

Here’s a table of options that you can use to create a lovely, balanced produce diet for your piggie.

Choose 2 things from the 80% column and 2 things from the 20% column-portioning them for the daily one cup.

Rule of thumb: serve a wide variety of vegetables.

80% of the cup (mostly green, leafy veggies)20% of the cup (other items)
Carrot tops (leaves)
Raspberry leaves
Red Leaf Lettuce
Collard Greens
Romaine (high in calcium)
Boston Lettuce
Wheatgrass (grown in a pot or tray)
Swiss Chard
Red Chard
Beet Greens
Celery Leaves
Radicchio Grass (watch out for grass w/ sharp edges)
Dill
Broccolini
Kale
Parsnips
Cilantro
Bell peppers (color doesn’t matter)
Red Cabbage
Green Cabbage
Coriander
Basil
Mint
Chinese Parsley

Each cavy has unique tastes and situations-including yours.  So, patiently tweak, adjust, and tailor your guinea pig’s meal.  Eventually, you’ll strike a balance between what your little friend likes, what’s best for his health, and what’s practical for you.

Another few tips to you blend your little friend’s daily cup of produce:

  • Make it enticing.  Provide a colorful variety of vegetables and fruits (less than veggies) to tempt and enthuse your piggie pal.  Switch up what you’re serving. 
  • Introduce new foods gradually.  If you want to experiment with new foods for your cavies, just give them small amounts at a time and then gradually increase them-that way you won’t upset your guinea pig’s stomach.
  • Keep them clean.  Thoroughly wash and clean all produce before serving your little friend. 
  • Only offer fresh produce.  Produce that is dried, canned, fried, frozen, defrosted, pickled or otherwise processed is bad (with a capital B) for your piggie pals.

So, what about fruit?  Can those be used as treats?  You can feed your guinea pigs fruit as a treat, but only serve it one or two times a week.  And the serving has to fit into your guinea pig’s allocation (one cup) of produce.

The high sugar content in fruit can make your guinea pig obese.  Being obese will start a domino-effect of health problems for your little friend- like diabetes, heart attacks, and strokes.

The list below includes some fruits (and non fruit treats) that are safe for guinea pigs to eat.

Once again.  Watch the portions of fruit (and other treats) that you give your guinea pigs.

Even if you don’t give your guinea pig fruit treats, weigh your guinea pig weekly.  It’s a good way to stay on top of any health issues with your cavies. Any significant weight change can be cause for concern.  

If you notice that your guinea pig has gained a lot of weight-one of the first things you should do (after contacting the vet)  is cut all fruit treats from his diet.  

Some good-intentioned owners unwittingly overfeed their little friends.  You don’t want that to be you. 

Foods to Avoid…at all Costs

Here’s a quick list of foods that you should never, ever….EVER give your guinea pig.  Everything on this list either disastrously high in fat (or sugar) OR will mess with your little friend’s digestive system and make him sick OR are poisonous and will kill your piggie pal.

  • Chocolate
  • Olives
  • Rhubarb
  • Peanut butter
  • Anything with dairy in it (includes yogurt, ice cream, milk, etc)
  • Tomato (and tomatillo) leaves and stalks
  • Any sort of hot or spicy veggies or herbs
  • Avocados
  • Baked goods: cake, cupcakes, cookies
  • Mushrooms
  • Dairy products like ice cream
  • Avocado
  • Nuts
  • Certain potatoes
  • Any drink with caffeine: coffee, sodas, and teas

Things to Remember About Your Piggie’s Diet

Feeding your guinea pig doesn’t have to be an overwhelming chore.  Just remember a few key things to keep you on track with your guinea pig’s diet:

  • An endless supply of high-quality fresh hay and water are necessary for your guinea pig’s health and happiness.
  • Vitamin C-enriched pellets (of the appropriate quantity and quality) should be given to your cavies.
  • Provide as wide a variety of produce as you can.
  • Treats are all right.  But, make sure the amount falls in your guinea pig’s allowed daily amount of veggies.
  • Limit fruits as well as other foods that are high in fat and sugar or processed.

Do these things (and follow the additional tips above) and you’re well on your way to providing your little buddy with a diet that will keep him fit, slim, healthy, and happy.

Related Questions

Why isn’t my guinea pig eating? 

First of all, if  you notice that your guinea pig isn’t eating, contact your veterinarian immediately.  There are many reasons why a guinea pig won’t eat: a change in environment, dental pain, a change in her diet, recent surgery, stress, gas, bloating are a few possibilities

Why do guinea pigs always need to be eating?  

Guinea pigs have very long colons, which moves the food they eat along slowly.  Tiny amounts of food are necessary to keep everything in the colon going in the right direction.  Depriving cavies of food for a long period of time is very dangerous to their health.

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Bankston, J. (2020). Caring for my New Guinea pig. Mitchell Lane.

Beck, A. (2013). Guinea pigs: Keeping and caring for your pet. Enslow Pub.

Feeding Guinea pigs. (n.d.). vca_corporate. https://vcahospitals.com/know-your-pet/guinea-pigs-feeding

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Guinea pig diet. (n.d.). Metropolitan Guinea Pig Rescue. https://mgpr.org/newsite/GP_Info/Guinea%20Pig%20Diet.htm

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Guinea pig Size-O-Meter. (n.d.). Pet Food Manufacturers Association. https://www.pfma.org.uk/guinea-pig-size-o-meter

Guinea pigs – Guinea pigs welfare – Tips, advice, health. (n.d.). The Largest Animal Welfare Charity in the UK | RSPCA. https://www.rspca.org.uk/adviceandwelfare/pets/rodents/guineapigs

Guinea pigs & vitamin C supplementation: What you should know. (2017, November 21). Mariposa Veterinary Wellness Center. https://www.mariposavet.com/guinea-pigs-vitamin-c-supplementation-know/

Is your Guinea pig’s diet providing the right nutrients? (2019, March 8). The Best Pet Health & Care Advice from Real Vets | PetMD. https://www.petmd.com/exotic/nutrition/your-guinea-pigs-diet-providing-right-nutrients

LibGuides: Plants toxic to animals: Plant names: Common. (1017). LibGuides at University of Illinois at Urbana-Champaign. https://guides.library.illinois.edu/c.php?g=745575&p=5339398

Mammals I – Veterinary preventive medicine. (n.d.). University of Minnesota Libraries – Pressbooks Publishing Platform. https://pressbooks.umn.edu/vetprevmed/chapter/chapter-15-mammals-i/

Vanderlip, S. L. (2003). The Guinea pig handbook. Barrons Educational Series.Vitamin C requirements of the Guinea-pig. (n.d.). PubMed Central (PMC). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1263201/

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