Dogs will anything once, twice if they weren't sure if they did or didn;t like it the first time... I doubt it will do him any harm other than like Eric mentioned, an supset tummy. Thinned out our chaeto pretty good here last week or so.... but if push comes to shove let me know and I'll dig you out some more, since it grows like mad for me anyhows it won't hurt anything. And it won't take any shipping, think we are only 20 mins apart.