Can guinea pigs eat mayonnaise? No — why, and what to do
Quick answer: No — mayonnaise is not safe for guinea pigs and should never be given.
Quick verdict
Unsafe
Key risk
Egg, oil and fat are harmful to herbivores.
Why
Guinea pigs cannot have mayonnaise.
Safe treats for guinea pigs instead
Guinea Pig Big-Bag Value Pack
A 10kg sack of Country Values fruity guinea pig nuggets with Timothy hay and a Vitamin C supplement — for households with several guinea pigs.
£32.99
Guinea Pig Monthly Essentials Food Bundle
A month of the basics for one or two guinea pigs: Timothy hay, Burgess nuggets, a daily vitamin C top-up and a bag of crunchy loops.
£24.99
New Guinea Pig Starter Kit
Everything to settle new guinea pigs in: a 3kg bag of Burgess nuggets, Timothy hay, a big bag of wood shavings and an edible hay bowl.
£29.49
Tiny Friends Farm Gerty Guinea Pig Tasty Mix
A nutritionally balanced muesli-style mix for guinea pigs, with added vitamin C
From£3.69
Can guinea pigs eat mayonnaise, and why?
Guinea pigs cannot have mayonnaise. Egg, oil and fat are harmful to herbivores.
Guinea pigs are herbivores who need unlimited hay or grass, a daily portion of fresh leafy veg, and a daily source of vitamin C — which they cannot make themselves. Their gut relies on constant fibre, so too much sugar or any sudden change can cause painful bloat and diarrhoea.
Warning — what to watch for
Egg, oil and fat are harmful to herbivores.
If your guinea pig has eaten mayonnaise, don’t wait for symptoms — contact your vet immediately, or call the Animal PoisonLine on 01202 509000 (24/7, UK). Signs of a problem can include vomiting, diarrhoea, drooling, lethargy, tremors or loss of appetite.
🚨 Find an emergency vet near youMore foods guinea pigs might eat
More for guinea pigs
If your guinea-pig has eaten mayonnaise, ring your vet — do not wait to see what happens. Treats made for guinea pigs, to give instead:
Vitakraft Guinea Pig Stick Honey 112g
Vitakraft Guinea Pig Stick Honey 112g: guinea pig treat sticks with wheat — 112g, two sticks
£4.05
Vitakraft Guinea Pig Kracker - Fruit 112g
Triple-baked guinea pig nibble stick on a wooden core, with oat and wheat flakes and added vitamin C.
£4.05
Johnson's Rabbit & Guinea Pig Seed Bar
A seed bar with dandelion and oregano, for rabbits and guinea pigs.
£2.99
Tiny Friends Farm Gerty Guinea Pig Tasty Nuggets
An extruded guinea pig food with stabilised vitamin C, formulated to prevent selective eating
£4.80
Feeding & nutrition guides
Frequently asked questions
Can guinea pigs eat mayonnaise?
Unsafe. Guinea pigs cannot have mayonnaise.
What happens if my guinea pig eats mayonnaise?
Egg, oil and fat are harmful to herbivores. If your guinea pig has eaten mayonnaise, contact your vet or the Animal PoisonLine (01202 509000) straight away — don’t wait for symptoms.
Is mayonnaise poisonous to guinea pigs?
Unsafe. Guinea pigs cannot have mayonnaise.
Free printable: safe & toxic foods for guinea pigs
mayonnaise is just one food — get the full one-page checklist of what’s safe, fine in moderation, or dangerous for guinea pigs. Vet-sourced, yours to print and keep.
Check mayonnaise for another pet
Sources
Our verdict on whether guinea pigs can eat mayonnaise draws on established UK and US veterinary and welfare organisations. Individual pets, quantities and preparation vary — always confirm with your own vet.