Many years ago our mid sized terrier mutt (approx. 30 lbs) had terrible gas. I put food grade diatomateous earth in his food (can't remember how much but got the info on a diatomateous web site) It worked almost immediately and I didn't need to continue it for long. It is totally safe to ingest but look up the amounts on sites for the benefits of diatomateous earth for pets. It also has many benefits for humans.