There could be a few different causes, and the IBD that you mention that the first vet diagnosed could be a cause. That would explain why prednisolone helps, as if relieves the inflammation. However, treating every day with pepto bismol is just putting a band aid on a big wound, and pepto is not a good thing to be giving anyway, as it has an aspirin-like ingredient that isn't good for ferrets. Two suggestions: First, replace the pepto bismol with Pepcid AC, which has only one active ingredient, Famotidine, which is safe for ferrets. Dissolve one 10-mg Pepcid AC tablet in 4.0 ml of water and give the ferret 0.25 - 0.4 ml 2 or 3 times a day, as needed, with the dosage depending on his weight and the severity of his problem. Store the liquid in the fridge and stir before using, as the dissolved tablet can settle at the bottom. Second, give him some probiotics. He's probably not producing enough 'good' bacteria anyway, which is needed for proper digestion, and the use of antibiotics is killing off what little 'good' bacteria he may have. The smell in the poops probably is excess bacteria, and the diarrhea is improperly digested food. Probiotics improve digestion and can help both problems. I have had great success using Forti-Flora for felines. I've also used plain acidophilus, and I know others who have used Bene-Bac. If you feed him some kind of soup, then any of these can be dissolved in water and included with the soup. If interested, write to me and I'll forward the link online where I buy the Forti-Flora. Acidophilus is in any drugstore or grocery store and is very cheap. Use about 1/4 tablet daily, then once every other day when symptoms improve. As a final possibility, carafate (sucralfate) can also help to soothe the stomach and to bind poops. Jeff In Memory of Neo, Trinity, Possum, Misty, Frodo, Baggins, and Mr. Parker Caring for Luna, Morphy, Baby Girl, Dozer, Pop, Sabrina, and Minnie Mouse [Posted in FML 6754]