I notice a couple of other people on that site complaining about other companies' products. It may be that they're buying something too strong for their beasties.

Still, it's a shame that any little animals have to suffer, whether the culprit is a company making bad products or an owner who doesn't read the package specs.

Then again, some critters don't tolerate any such products well. We've always used prescription stuff for Sassy (which she hates, because it burns).