Does your guinea pig get enough vitamin C? Build a day's greens
Guinea pigs can't make their own vitamin C, so it has to come from food every day. Here is where it comes from (hay, fresh pellets and vitamin C-rich veg), which vegetables help most, and which foods to avoid.
Tap the veg you offer in a day to see a rough vitamin C total for your pig, and learn when to ask a vet instead.
Why guinea pigs need vitamin C from food
Most animals make their own vitamin C. Guinea pigs cannot, just like people. If it is missing from the diet for long, a guinea pig can become seriously ill, so the answer to "does my guinea pig get enough?" is worth checking rather than guessing.
The good news is that it is easy to cover with ordinary food. A veterinary school guide puts the need at roughly 10–30 mg a day, and a welfare guide for schools gives 10 mg per kg of body weight. Both fit the same simple plan: good pellets, plenty of vitamin C-rich vegetables, and fresh food every day.
Where it comes from: three sources
- Hay and grass are the base of the diet, around 85–90% according to the PDSA. They keep the gut and teeth working but are not your main vitamin C source.
- Guinea pig pellets are made with added vitamin C. It breaks down over time and faster in air, so use a fresh portion each day, store the bag somewhere cool, dry and dark, and use it up within about three months of milling or buying. Never use a muesli-style mix.
- Fresh vegetables and herbs are the other big source. The PDSA suggests about a cup a day per guinea pig, spread over at least five or six different kinds.
Build a day's greens
Tap the veg you offer in a typical day. The tool adds up a rough vitamin C estimate for one guinea pig, using food-table values for raw vegetables and a typical handful. It is a guide, not a lab test: vitamin C drops as veg wilts, and every pig eats a bit differently.
Pellets and hay are the base. A few vitamin C-rich vegetables every single day cover the rest.
Which vegetables are worth it?
Bell peppers (any colour) are the easy winner: lots of vitamin C, and most guinea pigs love them. Parsley, kale and broccoli are also rich, but go gently. Welfare groups list kale and broccoli as foods for a few times a week rather than every day, and broccoli and cabbage can cause gas in big amounts. Lettuce, cucumber and celery are fine and hydrating, but they give very little vitamin C, so they should not be your only greens.
Sources differ on a few details. The RSPCA lists citrus as something to avoid, and the PDSA says fruit only in very small amounts, so treat fruit as a rare nibble, not a vitamin C plan.
Foods to keep away from
- Potato and potato skins, onion, garlic, chives, mushrooms, avocado, rhubarb and its leaves, and tomato leaves and vines. The tomato fruit itself is fine.
- Iceberg lettuce: very little goodness, and not recommended.
- Apple pips, which are poisonous.
- Lawn clippings, which ferment quickly, and wild plants from roadsides or treated lawns.
- Sugary shop treats and muesli mixes where the pig picks out the sweet bits.
Common mistakes
- Vitamin C in the water. The PDSA advises against it: sunlight weakens it and the taste can put pigs off drinking. If you want a supplement, follow your vet's advice on how to give it.
- Old pellets. A big bag opened in spring may be low on vitamin C by autumn. Buy smaller bags.
- Sudden changes. Introduce new foods, including a new pellet brand, gradually over two to four weeks to avoid upset tummies.
When to ask a vet
This guide is about everyday feeding, not diagnosing. Contact a vet if your guinea pig eats less, loses weight, stops passing droppings, seems stiff or reluctant to move, or if you think it has eaten something poisonous. A guinea pig that stops eating can become seriously ill quickly. If your pig has a bladder or urinary condition, ask the vet before changing calcium-rich foods like kale and parsley.