Re SIBO. The aim is to kill whatever is in the small intestine. In a healthy gut you have this nice system that works by applying acid then alkali, and by using enzymes and bile to try to tear the bacteria apart. The combination of enzymes acid and bile is mean to do that. Myhill suggests going further by taking vitamin C to bowel tolerance. Which is to say you increase the dose stepwise say 2g then 3g then 4g and take it to the point where you get diarrhoea then step back to a 1 g lower dose. She also suggests starving the microbes out by eating few readily available carbs. The 1st time I tried this (before I got the betaine HCL) I just had leaves (spinach, lettuce, kale etc) and home made fermented vegetables (eggplant, cabbage, carrots, cucumbers), meat and maybe a bit of olive oil for two weeks. It lead to improvements but did not stop the SIBO, I wish I had learned about Betaine HCL back then. I went on a really long journey trying lots of things that may have helped or harmed, and was already taking ox bile, enzymes and eating a whole foods diet and then adding betaine HCL just fixed the SIBO. If the above steps are not enough I would suggest looking at Grace Liu's 7 steps https://thegutinstitute.com/cure-sibo Only when choosing probiotics I would always check out ken lessesen's site first http://cfsremission.wordpress.com/. I would also look at his info on herbs their interactions with the microbiome.