FaunaHub

Small pets Nutrition & feeding

What to Feed Guinea Pigs

In short

Guinea pigs are herbivores whose diet should be based on unlimited grass hay, plus daily fresh leafy greens, a measured amount of guinea-pig pellets, and constant fresh water. Crucially, guinea pigs cannot make their own vitamin C and must get it from their diet every day, or they can develop deficiency. This is general guidance — your veterinarian can confirm what suits your guinea pig.

The foundation: hay, greens, and water

  • Grass hay, available at all times — the bulk of the diet, essential for digestion and dental wear.
  • Fresh leafy greens daily, which also help supply vitamin C.
  • A measured amount of plain guinea-pig pellets (formulated for guinea pigs).
  • Constant access to clean, fresh water.

The vitamin C requirement

This is the single biggest way guinea pig feeding differs from rabbits.

  • Unlike most animals, guinea pigs cannot synthesise vitamin C and need a daily dietary source.
  • Suitable fresh vegetables and guinea-pig pellets help provide it; your vet can advise on supplementation if needed.
  • Too little vitamin C over time can lead to deficiency (sometimes called scurvy) — a reason to keep the diet consistent.
  • Use food formulated for guinea pigs, not rabbit food, which is not designed for their vitamin C needs.

Guinea pig feeding checklist

  • Keep grass hay available at all times.
  • Offer daily leafy greens that help supply vitamin C.
  • Provide a measured amount of guinea-pig-specific pellets.
  • Ensure constant fresh water.
  • Ask your vet about vitamin C and any signs of deficiency.

What not to assume

  • Do not feed rabbit food to guinea pigs — it is not formulated for their vitamin C needs.
  • Do not rely on pellets alone; hay and fresh greens matter.
  • Do not assume vitamin C stores last — they need it daily.
  • Do not change the diet abruptly.

When to ask a veterinarian

Nutrition is individual, and this page cannot assess your specific pet. Ask a licensed veterinarian — ideally before major changes — especially in these situations.

  • Puppies, kittens, pregnancy or nursing, or seniors — life stages with particular needs.
  • Weight concerns, a changing body condition, or any recommended weight-loss or weight-gain plan.
  • Any diagnosed condition or prescription diet (for example kidney, urinary, diabetic, or allergy diets).
  • Vomiting, diarrhoea, appetite loss, or refusal to eat that lasts or keeps coming back.
  • Before a major diet change, or if you are considering a raw, vegetarian, or home-prepared diet.

What to Feed Guinea Pigs — Frequently Asked Questions

Why do guinea pigs need vitamin C in their food?
Unlike most animals, guinea pigs cannot make their own vitamin C, so they must get it from their diet every day. Suitable fresh greens and guinea-pig pellets help provide it; a veterinarian can advise on supplementation.
Can guinea pigs eat rabbit food?
It is not recommended. Rabbit pellets are not formulated for a guinea pig's vitamin C requirement and differ nutritionally. Use food made specifically for guinea pigs.
What is the base of a guinea pig's diet?
Unlimited grass hay, supplemented with daily leafy greens, a measured amount of guinea-pig pellets, and fresh water. Hay supports digestion and helps wear down their continuously growing teeth.

Sources and further reading

Authoritative references used for general educational context. External links open in a new tab and these organisations do not endorse FaunaHub. Specific feeding amounts and diet choices depend on the individual animal and should be confirmed with the food label and a licensed veterinarian.