I noticed that my doodle would throw up(mostly greenish/brown liquid) the morning after having a Greenie, so we stopped giving them to him and he hasn't vomited since. My doodle does 'gulp', so I did notice large pieces of Greenies in his poop...I suppose he may have been having short lived partial bowel obstructions(?). Now, if I plan to give him a greenie, I'll warm it in the microwave in a wet towel and cut it up for him...sort of defeats the purpose though, so I'm not going to buy them anymore.