As someone else has already mentioned, they are vegetable oil. The horse will probably lip it, realize it tastes bad, and not give it a second thought. My horses hate when we put them up to play paintball. They look forward to going back to the pasture to play!! They are used to them and don't swallow them. But even if they do swallow the shell itself, it dissolves pretty quick. Try it, put a paintball in just water and see what happens! That is just water, the horses stomachs have acids and such that would dissolve it faster. Paintball, horses, YOU ROCK!!!!