As acids go, boric acid is very weak. A dilute solution of boric acid is commonly used (by people) as an eyewash. The solid is a white powder, and probably tastes very nasty. I really doubt that a ferret would be interested in it enough to ingest a harmful portion, but then again, it's always better to be safe than sorry, I s'pose. Of all the pesticides you could use, however, boric acid would probably be the least harmful to your pets. Jen [Posted in FML issue 1339]