don't give your guinea pig anything your not sure of without consulting a vet. my guess, is, as I have two rodents of my own, that anything with sugar or a very strong taste, like peppermints do, would upset their stomach. they have small bodies, and can't deal with anything to strong. but the best way to find out is to ask a vet, before then , I wouldn't give them to your guinea pig. it doesn't sound for healthy for him/her.