I don't use them myself because I see no health benefit for the risk for me personally. I have other things for them to chew on and with my dogs they can and do chew them up waaaay faster than a bully stick or bone, it's too soft for them, and their floppy jowls hide it while they are chewing so I would never be able to see how big of a piece they had actually gotten off, since they gnaw with their back teeth, unless I was laying on the ground in front of them with my face in their face and even then I most lkely couldn't see in their mouths. So I don't necessairly blame greenies, I just have no desire to use them myself, too expensive for no benefit in my case. I find bully sticks and raw bones better for my two and those are the only chews they get.