After being on antibiotics CONSTANTLY as a child and teenager, I suffered a lot of ill-effects and I have been killing candida and healing my gut since the early 90s, off and on. IMO, these are simply the best on the market, and much better than the "regular" Primal Defense. After reading some bad reviews, I wanted to point out a few things others may find helpful. First off, probiotics aren't magic, and if they are magic to some folks, that's great!! But let me take this a step further. Mostly everyone that has bowel problems, and allergy problems especially, have leaky gut syndrome. If you are REALLY sensitive to this product, you probably have leaky gut and will never recover if you don't heal your intenstinal tract. I have found great recovery with a couple of products that some may find helpful: Colostrum LD and MSM (both vendors are here at Amazon). I have been on high doses of both of these and I feel better than I have in years. I used to have severe bloating, extreme fatigue, severe food allergies/sensitivies, extreme chemical sensitivies, carb sensitivity, skin problems, cravings, IBS symptoms, uveitis (corneal inflammation), etc.....but I always tried to do my own research because I knew doctors caused all of this to begin with by keeping me on antibiotics constantly. Please keep in mind that if you have a severe case of leaky gut syndrome, probiotics may not work well for you and you'll probably never *fully* recover. Also, certain strains of probiotics work better for certain symptoms than others. If I took a certain probiotic for IBS, I would get worse constipation because that strain of probiotic is for people with diarrhea. Lesson learned. Also, if you have candida problems, I find it's best to start out with Syntol and then go to this brand. Syntol is great and very helpful. But saying all of that to say, this particular probiotic has helped me tremendously and I don't ever want to be without it. To actually have energy and function like a normal person is great