Hi there, first time poster, long time lurker. Have a 1 year old boy that’s been having various degrees of soft stools for about 6 months. He got tested twice for regular parasites and both tests came back negative. I recently did a PCR test though that came back positive for Clostridium Perfringens, at about 800,000/g. Before doing the PCR test, my vet gave me a week’s worth of Metronidazole to try out, but it did nothing at all on him. When the results came in, she said we could try Amoxicillin instead for two weeks OR do nothing at all and wait until the bacteria clears by itself... She said that since he seemed to be Metronidazole-resistant, the Amoxicillin might not work on him either. She didn’t suggest anything else. I literally read all the threads and articles written about C. Perf and antibiotics (what a headache) and it seems that the results vary from: the diarrhea clears up only when the cat is on the meds but then comes back as soon as the meds are over, or, it doesn’t do much at all. After reading about S. Boulardii and its good results though, I decided to try out Renew Life BoulardiiMAX with 10 billion CFUs. The reason I chose this brand is that it only contains 1 ingredient and that is S. Boulardii, nothing else. I see a lot of people refer Nutricology, but I don’t know how I feel about it containing Hydroxypropyl Methylcellulose (a corn derivative?), Microcrystalline Cellulose (toxic in mammals?), Silicon Dioxide (contributes to urolithiasis?) and Stearic Acid (made from cottonseed which has a high content of pesticide residue that can damage the liver?) - all inactive ingredients that seem to be better off avoided. The brand AOR contains Sodium Stearyl Fumarate (a corn derivative?). The brand Sisu contains Magnesium Fumarate as well as Microcrystalline Cellulose. And the much-liked Jarrow & MOS not only has Maltodextrin, but also Vitamin C (contributes to the formation of stones in the urinary tract?), Magnesium Fumarate and Silicon Dioxide. Hence, Renew Life seemed like a cleaner choice to me. I just don’t know if I want to risk adding anything else to the mix that might potentially cause harm to him down the road. But since the capsules are 10 billion CFUs, I give him half of that for the whole day, so 5 billion CFUs in actuality. I split that in two, so I give him a 1/4 in the morning and a 1/4 in the evening (2.5 billion each time basically). Tomorrow will be week that I started the treatment - I see a tiny bit of improvement but not much (sometimes the stools are very nice clean logs, sometimes they're quite soft-serve). I know I should give it to him for a whole month, so I'll wait patiently. A few questions for now: - Is this dosage OK, or should I try to find a brand that actually contains 5 billions CFUs instead so that he gets a "larger" amount of powder at each feed? What happens if I give him the 10 billion CFUs? - My vet said that the C. Perf could sometimes be a secondary infection due to an IBD for instance. Would I be able to determine that the cause is indeed more of an inflammatory/digestive/food issue IF he doesn’t get better after a month? Or could it be a question of trial and error until I find the right brand and right dosage for him? The vet put him on ZD for now. I have two hypotheses as to where he could've gotten the bacteria from. One is from a potentially bad batch of canned food he turned his nose to, but then nibbled on it anyway for a few minutes. And the other is from when he got neutered at the ASPCA, who knows. It started right after that. Anyway, thanks in advance!