Guinea pigs can’t make their own vitamin C, can’t vomit, and have a digestive system built for one thing: grass. That combination makes food mistakes more serious for them than for most pets. Here’s the complete safe/unsafe list, portion guidance, and the foods that send guinea pigs to the vet most often.
What should a guinea pig’s diet look like?
Roughly 80% hay, 10% fresh vegetables, 5% pellets, 5% treats. Unlimited grass hay (timothy, orchard, meadow) keeps their constantly-growing teeth worn and their gut moving. Adults need 10–30 mg of vitamin C daily from food — deficiency causes scurvy within weeks.
Which vegetables are safe every day?
- Bell peppers (all colours) — the single best daily veg: high vitamin C, low sugar.
- Romaine and leaf lettuce (never iceberg — near-zero nutrition and can cause soft stools).
- Cucumber — hydrating, safe daily in slices.
- Coriander/cilantro and parsley (parsley a few times a week — higher in calcium).
- Zucchini/courgette — safe daily.
Which foods are safe 2–3 times a week?
- Carrots — sugary; a thin slice or two, not a whole carrot.
- Tomatoes — ripe fruit only; stems and leaves are toxic.
- Broccoli, cabbage, kale — nutritious but gas-forming; small amounts.
- Spinach — high oxalates; occasionally, small amounts.
- Fruit (apple without seeds, strawberry, blueberry, small melon cubes) — treat-sized pieces once or twice a week; think “postage stamp”, not “slice”.
What can guinea pigs never eat?
These cause emergencies, not upset tummies:
- Anything from the onion family — onion, garlic, leek, chives: damages red blood cells.
- Avocado — fatty and contains persin.
- Chocolate, caffeine, alcohol — toxic to the heart and nervous system.
- Potato, potato peels and green tomato parts — solanine poisoning.
- Rhubarb (leaves and stalks) — oxalic acid.
- Iceberg lettuce in quantity, dairy of any kind, meat — their gut simply cannot process them.
- Bread, crackers, cereal, nuts and seeds — choking and gut-blockage risks; seeds also fatty.
- Houseplants and garden clippings — many (lilies, buttercups, foxglove, daffodils) are highly toxic; lawnmower clippings ferment and cause deadly bloat.
How do I make sure my guinea pig gets enough vitamin C?
One-eighth of a bell pepper daily covers most of the requirement. Skip vitamin drops added to water — they degrade in light, make water taste bitter, and reduce drinking. Food sources or a vet-recommended tablet are more reliable. Signs of deficiency: lethargy, rough coat, swollen joints, reluctance to walk, bleeding gums.
What do I do if my guinea pig ate something toxic?
Do not try to make them vomit — guinea pigs physically cannot. Remove the food, note what and how much was eaten, and call an exotics-savvy vet immediately. A guinea pig that refuses food for more than 6–8 hours is an emergency in itself (gut stasis), regardless of the cause.
FAQ
Can guinea pigs eat grass from the garden?
Yes — fresh-picked, unsprayed grass is excellent. Introduce gradually in spring, and never feed mower clippings.
Can guinea pigs eat rabbit food?
No. Rabbit pellets lack vitamin C and some contain antibiotics that are dangerous to guinea pigs.
Can baby guinea pigs eat the same vegetables as adults?
From about 3–4 weeks they can nibble the same safe vegetables in smaller amounts, alongside unlimited alfalfa hay for calcium — switch to grass hay around 6 months.
This guide is general information, not a substitute for veterinary advice. When in doubt, call your vet.
