What to Feed a Guinea Pig
Unlimited hay, about 1/8 cup of plain pellets, and vitamin C veg every day. How to pick, portion, switch and store guinea pig food.
A guinea pig's day is mostly hay. Pellets are a small daily portion, and fresh vegetables fill the gap that matters most: vitamin C.
Guinea pigs can't make their own vitamin C, so it has to come from food every single day. Get the hay, the veg and fresh pellets right and most of the job is done.
At a glance
- Best staple Unlimited grass hay, all day and night
- Pellets About 1/8 cup a day for an adult
- Fresh veg Every day, green bell pepper first
- Vitamin C Every day, from veg and fresh pellets
- Switching Slowly, over four weeks
- Avoid Rabbit pellets, seed or fruit mixes, water drops
Hay comes first
Unlimited fresh grass hay, there all day and night. It's most of the diet.
- Hay rack: keep it full of timothy or orchard grass hay. Top it up whenever it looks low.
- Heavy dish: a heavy bowl for the small pellet portion, so it can't tip.
- Water bottle: fresh water always. Tap the ball each day and a drop should come out.
- Hide: one hide for each guinea pig, so everyone has a place to rest.
- Hay rack: keep it full of timothy or orchard grass hay. Top it up whenever it looks low.
- Heavy dish: a heavy bowl for the small pellet portion, so it can't tip.
- Water bottle: fresh water always. Tap the ball each day and a drop should come out.
- Hide: one hide for each guinea pig, so everyone has a place to rest.
Chewing hay wears down growing teeth and keeps the gut moving.
- Adults: timothy or orchard grass hay.
- Young, pregnant or nursing: alfalfa hay, which has the extra nutrition they need.
- Alfalfa for a grown guinea pig: only a pinch now and then as a treat. It's too high in calcium for adults.
Pellets: a small daily portion
About 1/8 cup a day for an adult. The bag is the final word.
- Plain pellets
- Seed and fruit mix
- Plain pellets
- Every piece is the same, so your guinea pig eats the whole balanced diet.
- Seed and fruit mix
- Avoid. Guinea pigs pick out the sweet bits and leave the rest.
Pick a plain pellet with stabilized vitamin C.
Do
- choose a timothy-based pellet for an adult.
- choose an alfalfa-based young formula for guinea pigs under 6 months, and for pregnant or nursing mothers.
Don't
- feed rabbit pellets. The Merck Veterinary Manual says they don't have enough vitamin C for guinea pigs.
- buy mixes with seeds, nuts, corn or dried fruit. Oxbow warns against them, and our care sheet calls them sugary and a choking risk.
Adults
About 1/8 cup (2 tablespoons) a day, plus unlimited hay. That's Oxbow's amount and the Merck Veterinary Manual's.
Young, pregnant or nursing
Oxbow says unlimited young formula. Mazuri says free choice.
Any plain formula below with vitamin C listed is fine. Match the base to your guinea pig's age.
Compare 7 guinea pig pellets: protein, fiber, calcium and vitamin C
| Food | Base | Protein | Fat | Fiber | Calcium | Vitamin C |
|---|---|---|---|---|---|---|
| Oxbow Essentials Adult | timothy | 14.0% min | 2.0% min | 25-28% | 0.35-0.75% | 250 mg/kg min |
| Oxbow Essentials Young | alfalfa | 18.0% min | 2.5% min | 18-23% | 0.60-1.10% | 400 mg/kg min |
| Oxbow Essentials Senior | timothy, oat, orchard, some alfalfa | 13.0% min | 2.5% min | 25-29% | not listed | 300 mg/kg min |
| Oxbow Garden Select Adult | timothy, oat, orchard | 12.0% min | 2.5% min | 22-26% | 0.35-0.75% | 250 mg/kg min |
| Oxbow Simple Harvest Adult | timothy | 12.0% min | 2.0% min | 22-26% | 0.40-0.80% | 250 mg/kg min |
| Kaytee Timothy Complete | timothy | 14.0% min | 2.0% min | 23% max | not listed | 200 mg/kg min |
| Mazuri Timothy-Based | timothy | 18.0% min | 4.0% min | 14-18% | not listed | 1,000 mg/kg min |
Figures are each maker's guaranteed analysis. The vitamin C figure is what the food had when it was made, not what's left months later.
Feeding schedule
Hay is always unlimited. Pellets and veg go in every day.
A sample week
Young (under 6 months)
Adult
Pregnant or nursing
Feed Optional Rest day
Show as a table
| Life stage | Hay | Pellets | Fresh veg |
|---|---|---|---|
| Young (under 6 months) | Unlimited, alfalfa | Unlimited young formula | Every day |
| Adult | Unlimited, timothy or orchard | Every day, about 1/8 cup | Every day, about 1 cup |
| Pregnant or nursing | Unlimited, alfalfa | Unlimited young formula | Every day |
Take wilting veg out after a few hours. Kaytee says rotting produce can make a guinea pig sick.
Fresh vegetables every day
About 1 cup of veg a day, leaning on vitamin C. Green bell pepper is the best staple.
- Every day
- Now and then
- Avoid
- Every day
- Green bell pepper is the best staple. Romaine and cilantro are good daily greens.
- Now and then
- Keep sweet foods small. Mazuri keeps fruit under 5% of the diet.
- Avoid
- Skip iceberg lettuce.
Every day
Green bell pepper is high in vitamin C and low in sugar. Romaine lettuce and cilantro round out the bowl.
Small amounts
Keep high-calcium greens like spinach small, to help prevent bladder stones. Mazuri says extras should be under 20% of the diet, and fruit under 5%.
Skip
Iceberg lettuce.
Vitamin C every day
They can't make it. It has to come from veg and fresh pellets every day.
- Healthy
- Vitamin C problem
- Healthy
- Alert, moving freely, eating well.
- Vitamin C problem
- Hunched, stiff or swollen joints, slow to move.
Oxbow explains that guinea pigs lack the enzyme to make vitamin C. Without it they get scurvy.
- Fresh pellets. The Merck Veterinary Manual says pellets can lose a lot of their vitamin C in just a few months. Buy fresh bags regularly.
- A tablet, if you want one. A vitamin C supplement is optional. Give it exactly as its label says.
- No drops in the water. Vitamin C breaks down quickly in water and changes the taste, so they may drink less.
Signs of scurvy:
- sitting hunched and puffed up, or tired
- stiff or swollen joints, not wanting to move
- bleeding gums
Switching foods
Change slowly. Oxbow's schedule takes four weeks.
Week 1: 75% old pellets, 25% new.
Week 2: half and half.
Week 3: 25% old, 75% new.
Week 4: all new pellets.
Sudden changes upset the gut. Go one week at a time.
Storing pellets
Keep the bag sealed, cool and dry, and buy a size you'll finish quickly.
Opened bag
Squeeze out the air and reseal it. Kaytee says use it within 30 to 45 days, and refrigerate or freeze for longer storage.
Unopened bag
Mazuri says use within a year of manufacture or by the best-by date, stored at 75°F or cooler.
Checking your guinea pig
Watch weight, appetite and teeth. Changes mean a vet visit.
Adult guinea pigs usually weigh 1.5 to 2.5 pounds. A healthy one eats hay all day and moves around freely.
- Underweight
- Healthy
- Overweight
- Underweight
- Bony along the back and hips.
- Healthy
- Smooth, evenly rounded body.
- Overweight
- Wide and heavy. Check the pellet and treat amounts.
- Normal
- Overgrown
- Normal
- Short, even front teeth.
- Overgrown
- Long teeth make eating hard.
Their teeth grow for life. Hay and safe wooden chews wear them down.
- dropping food or drooling
- not eating
- long or uneven front teeth
Quick answers
How much pellet does my guinea pig get? About 1/8 cup (2 tablespoons) a day for an adult, plus unlimited hay. Young, pregnant or nursing guinea pigs get unlimited young formula. The bag is the final word.
Can I feed rabbit food? No. The Merck Veterinary Manual says rabbit pellets don't have enough vitamin C for guinea pigs.
Why does pellet age matter? Vitamin C breaks down over time. Pellets can lose a lot of it in a few months, so buy fresh.
Alfalfa or timothy? Timothy or orchard for adults. Alfalfa-based food and hay for guinea pigs under 6 months and pregnant or nursing mothers.
Is a seed mix fine? No. Oxbow says to avoid mixes with nuts, corn, seeds or fruit. Guinea pigs pick out the treats and skip the rest.
How do I switch brands? Slowly. Mix new into old over four weeks.
Should I add vitamin C drops to the water? No. It breaks down fast in water and can put them off drinking. Use vitamin C veg, fresh pellets, and a tablet if you want one.
Shop this
Pick up in store or have it shipped.
Reviewed by our team 2026-11-06. Nutrition figures are each maker's published guaranteed analysis.
