This is what I could find about the herbs. Both are believed to helpful for diabetics. It would seem to me that they would be fighting against the pred, but I'm not an herbalist. And who knows how the two herbs are reacting to each other. Note the precautions for both herbs: http://www.botanical.com/products/learn/d/devils_club.html http://www.botanical.com/products/learn/g/gymnema.html I found a website of a shelter that recommends the use of Devils Club. http://www.newrainbowbridge.com/herbal/devils_club.htm http://www.newrainbowbridge.com/herbal/DCS_faq.htm If she is using the Gaia brand Devils Club Supreme then there are other herbs in it, as well as alcohol as a preservative. It is noted on the this site that Gaia has discontinued making it. I hope she discusses this with her vet. If he's basing his decision to take this ferret off the pred without knowing about the herbs it could very well be a wrong decision. Tracy [Posted in FML 6153]