By Priya Nair (RVN) and Lachlan Ortega · Last updated 17 May 2026
This is the page we reach for when somebody messages us at 11pm saying “the guinea pig ate the kid’s [whatever] — what do I do?” It’s our team’s working food list, kept in alphabetical order, with portion sizes that work for an average 900g-1.1kg adult guinea pig.
If the food you’re worrying about isn’t here, the safe default is “don’t, and ring an exotic vet”. Guinea pigs cannot vomit, so anything that’s gone in has to come out the long way.
The 80/15/5 rule (recap)
- 80% hay — unlimited grass hay (Timothy, orchard, meadow). Alfalfa only for pigs under 6 months or pregnant sows.
- 15% fresh veg — about 1 cup per pig per day, ideally split into two meals.
- 5% pellets — 1/8 cup per day, plain Timothy-based, no muesli mixes.
- Treats — fruit, occasional treats. Not daily. The single biggest cause of guinea pig obesity we see is “just one grape” turning into ten.
Vitamin C requirements: ~10-30mg/day for a healthy adult, more for pregnant or recovering pigs. Most pellets list Vit C content but it oxidises within weeks of opening — never rely on pellets alone. A piece of bell pepper daily covers it.
Quick safe/unsafe table — everything we’ve reviewed
| Food | Safe? | How much | Detail |
|---|---|---|---|
| Aloe vera | ❌ | None | Latex irritates the gut |
| Asparagus | ✅ | 1-2 spears, 2x/week | High in oxalates — small amounts |
| Avocado | ❌ | None | Toxic — persin + fat content |
| Banana | ⚠️ | 1 thin slice, 1x/week | High in sugar |
| Bell pepper (capsicum) | ✅ | 1/8 pepper daily | Vit C champion — daily staple |
| Blueberries | ✅ | 2-3 berries, 2x/week | Antioxidants, mild sugar |
| Bread | ❌ | None | No nutritional value, causes bloat |
| Broccoli | ⚠️ | 1 small floret, 1x/week | Causes gas in larger amounts |
| Cabbage | ⚠️ | 1 small leaf, 1x/week | Gas — savoy worse than green |
| Candy / lollies | ❌ | None | Sugar, additives, no use |
| Carrot | ⚠️ | 1 small piece, 2x/week | High sugar. Tops are great daily. |
| Cauliflower | ⚠️ | 1 small floret, 1x/week | Gas — leaves better than head |
| Celery | ✅ | Small piece, chopped | Chop strings or they catch in throat |
| Cherries | ⚠️ | Half a cherry, no stone | Stones contain cyanide compounds |
| Chocolate | ❌ | None | Theobromine toxicity |
| Collard greens | ✅ | 1-2 leaves, 3x/week | Great Vit C + calcium balance |
| Corn (kernels) | ⚠️ | A few kernels, occasional | Starchy — limit. Husks/silks safer. |
| Corn husks & silks | ✅ | Small amount, 2x/week | Fibre rich, low sugar |
| Cranberries | ⚠️ | 1-2, occasional | Tart, low sugar — fresh only |
| Cucumber | ✅ | 1-2 slices daily | Hydrating, low cal |
| Dairy (cheese, milk, yog) | ❌ | None | Cannot digest dairy |
| Garlic / onion / chives / leek family | ❌ | None | Toxic to red blood cells |
| Grapes | ⚠️ | 1 grape halved, 1x/week | High sugar, but loved |
| Green beans | ✅ | 2-3 beans, 2x/week | Choose stringless, fresh |
| Iceberg lettuce | ❌ | None | Causes diarrhea — water + nothing else |
| Kiwi | ✅ | 1 small slice, 1-2x/week | Excellent Vit C |
| Kale | ⚠️ | 1 leaf, 2x/week | High calcium — alternate with lower-cal greens |
| Lettuce (romaine/green leaf) | ✅ | 2-3 leaves daily | NOT iceberg. Romaine ideal. |
| Mango | ⚠️ | 1 small piece, 1x/week | Very sweet — treat only |
| Mint | ✅ | 1-2 leaves, 2-3x/week | Some pigs love, some refuse |
| Mushrooms | ❌ | None | Many varieties toxic — never risk |
| Nuts / seeds | ❌ | None | Choking + fat, no nutritional fit |
| Parsley | ✅ | Small sprig, 3x/week | High Vit C and calcium — rotate |
| Peas (fresh) | ✅ | 2-3 peas, 1-2x/week | Pod is fine too |
| Pineapple | ⚠️ | 1 small piece, 1x/week | Acidic — small only |
| Potato (raw or cooked) | ❌ | None | Solanine + starch |
| Pumpkin | ⚠️ | 1 small cube, 1x/week | Cooked safer than raw |
| Raisins | ⚠️ | 1-2, 1x/week max | Concentrated sugar |
| Raspberries | ✅ | 1-2 berries, 2x/week | Leaves edible too |
| Rhubarb | ❌ | None | Oxalic acid — leaves especially toxic |
| Spinach | ⚠️ | 1 small leaf, 1x/week | High oxalates — limit |
| Strawberries | ✅ | 1 small strawberry, 2x/week | Hulls fine, leaves great |
| Sweet potato | ⚠️ | 1 thin slice raw, 1x/week | Cooked OK in tiny amounts |
| Tomato (red flesh) | ✅ | 1 small piece, 2-3x/week | NO stems, leaves or green tomato |
| Watermelon (flesh) | ⚠️ | 1 small piece, 1x/week | Rind is actually safer (less sugar) |
| Zucchini | ✅ | 1-2 slices, 2-3x/week | Low cal, hydrating |
The “absolutely never” list
These show up in our emergency emails most often. If your guinea pig has eaten any of these in a meaningful quantity, ring an exotic vet now:
- Avocado — persin + extreme fat content. Even small amounts cause distress.
- Onion family — onion, garlic, leek, shallots, chives. Damages red blood cells.
- Chocolate — theobromine. As toxic to guinea pigs as it is to dogs, gram for gram worse because of body weight.
- Iceberg lettuce — not “toxic”, but causes severe diarrhea in volume.
- Rhubarb (especially leaves) — oxalic acid.
- Potato and potato leaves — solanine.
- Mushrooms — risk of misidentification, not worth the upside.
- Dairy — guinea pigs lose lactase after weaning. Yogurt drops should never have existed.
- Meat or fish — they’re herbivores. Their gut is not built for it.
- Anything cooked, salted, sugared, or seasoned — including “human food” leftovers.
- Bread, crackers, biscuits, cereal — empty starch + sugar, contributes to obesity and dental issues.
- Tomato leaves & stems, green tomato — the red flesh is fine, but anything green on a tomato plant has solanine.
- Houseplants in general — assume toxic unless you’ve confirmed otherwise.
The daily plate — what we actually feed
Here’s a real week of feeding for our three pigs. We rotate so that no veg gets boring, but also so no single high-oxalate or high-calcium green is overdoing it.
| Day | Morning | Evening |
|---|---|---|
| Monday | Romaine + bell pepper + coriander | Cucumber + parsley + a few grapes |
| Tuesday | Green-leaf lettuce + bell pepper + carrot top | Celery + 2 strawberries |
| Wednesday | Collard green + bell pepper + dill | Cucumber + basil |
| Thursday | Romaine + bell pepper + a few blueberries | Zucchini + parsley |
| Friday | Green beans + bell pepper + cilantro | Carrot top + small piece of mango |
| Saturday | Romaine + bell pepper + kale (small) | Cucumber + raspberries |
| Sunday | Bell pepper + mixed herbs + zucchini | Tomato (small) + parsley |
Hay: brands, types, what we buy
- First-cut Timothy — coarse, stalky, great for tooth wear. Default for adult pigs.
- Second-cut Timothy — softer, leafier, better for picky eaters.
- Third-cut Timothy — very soft, more leaf less stalk. Best for sick or elderly pigs.
- Orchard grass — slightly sweeter, great variety.
- Meadow hay — mixed grasses, what most UK/AU buyers will see locally.
- Alfalfa — high calcium, high protein. Pups under 6 months, pregnant/nursing sows, or as a recovery food. Not long-term for adults.
Treats that aren’t terrible
Most commercial guinea pig “treats” are sugar bombs. If you want a reward food for hand-taming or floor time:
- A piece of bell pepper (Vit C bonus)
- A single blueberry
- A small wedge of cucumber
- Hay-stuffed paper roll (enrichment + food in one)
- Dried herbs from a clean source (dill, basil)
When diet goes wrong
The two diet-related emergencies we see most often:
1. GI stasis from low hay intake. Pig eats less, poops smaller and fewer, stops drinking. Without fast intervention (sub-cut fluids, motility drugs, critical care formula syringed in), this kills within 24-48 hours. Hay intake matters more than anything else on this list.
2. Bladder stones from too much calcium. Especially common in pigs fed lots of alfalfa, kale, or spinach with hard water. Symptoms: blood in urine, hunching when peeing, weight loss. Surgery is the usual treatment.
A balanced rotating diet of mostly hay, with leafy greens and bell pepper as daily staples and high-calcium veg like kale and parsley used in moderation, avoids almost all diet-related problems we see in clinic.
Sources
- RSPCA UK — Guinea pig diet
- UC Davis School of Veterinary Medicine — Guinea pig health topics
- Our own complete guinea pig care guide for housing, social and vet basics
We get asked — guinea pig food FAQ
How much fresh veg should a guinea pig eat per day?
About 1 cup of fresh vegetables per pig per day, ideally split into two meals (morning and evening). Hay should still be 80% of the diet and available unlimited. Pellets are a small daily addition, not a meal replacement.
What’s the most important nutrient for guinea pigs?
Vitamin C. Guinea pigs cannot manufacture their own and must get it daily from fresh food. Bell pepper is the gold-standard source. Vitamin C in pellets oxidises within weeks of opening, so don’t rely on pellets alone. See our food safety master list for daily portion guidance.
What signs should send me to a vet?
- Not eating for 12+ hours (GI stasis — emergency)
- Not pooping (or smaller, drier poops than usual)
- Crusty eyes, wheezing, or sneezing more than once a day (URI)
- Hunched posture, fluffed coat, hiding
- Sudden weight loss (weigh weekly to catch this early)
- Blood in urine, hunching when peeing
A pig that hasn’t eaten in 12 hours is an emergency, not a “wait and see” situation. More detail in our vet warning signs pillar.
Related reading
- The complete guinea pig care guide — diet, housing, social pairs, lifespan
- Master food safety table
- Cage setup & size guide — most pet-shop cages are too small
- RSPCA UK — Guinea pig welfare standards
Page last updated 17 May 2026. We re-check our pet-care content regularly and update when something changes.
