They’re pretty big so you probably wouldn’t be able to swallow one. They’re a bit smaller than a quarter but quite thick. It’d start to expand in your mouth as soon as it got a little wet and you’d (hopefully) realize immediately that you’re not supposed to swallow it. If you ignored all of that and forced yourself to swallow it, then you’re probably going to choke as it expands. If you somehow got it in your stomach, then it’ll expand in there and you’ll have other serious issues.