I don't exactly agree with that. I mean every food can cause a blockage if eaten in amounts to large to digest. I think greenies can be eaten but have to be monitored. If your dog chews off a big piece, swallows it, and then gets sick because he was able to digest it, I don't think that is the Greenies fault. Also like someone had already posted: A lot of foods expand when they are soaked. Just my opinion.