Krista, yes you can use echinacea on ferrets. Just not 24/7. Like people you cant' use it for extended periods of time , you can use it without problems in no more than 2wk intervals. I make up a batch of linitone with many herbs to help with imunity like echinacea as well as herbs to help prevent cancer, or put cancer in remition,(ihave one I use for adrenal, is a combination of herbs that has cured one ferret that I know of with this cancer) any more questions about herbs, you can e-mail me at [log in to unmask] Debi of Fuzzy Loving Ferret Rescue weasle queen [Posted in FML issue 4929]