"My guinea pig does not chew on any of the other chew toys I have bought him (wood, lava rocks, salt things, those 'crispy' round things) and I was starting to worry about his teeth. However, I put one of these in his cage and he will nibble on it over about 4 days until it is gone. I also like that this treat has Vit C. The other vitamins I have tried (like the kind you add to their water) work fine I suppose, but made his urine STINK! These do not have that effect. I would not consider this item as a treat so much as an edible chew toy with vitamins."