Salad (lettuce) is notoriously hard to digest, as are all raw vegetables. And it causes gas because it ferments in the bowel. Adding anything to your diet when you have an increasingly sensitive digestive system has to be done very slowly. So you eat a very small salad along with something you know doesn't cause problems (usually) and increase very very slowly until your body adjusts. This can take weeks, maybe never will actually. As we age, I'm discovering very unwillingly, our body changes how it works. I went from eating anything I wanted without thinking about it to having to think twice before eating anything, especially something new in my diet, over the past 20 years. Since the moron in the ER literally messed up my body for the rest of my life (it seems), my diet has become increasingly restricted. Happily, or probably more likely quite unhappily, I don't care about eating any more so I do it just to survive. I'm only 5 feet tall and very petite, the size of a twelve year old probably, but I went from 120 pounds to 105. That's not good. I haven't weighed 105 pounds since I was in my late 20s. When you're old, you need some weight to lose, just in case. After the December fiasco with the augmentin poisoning, I ate very unhealthily, cake, cookies, ice cream, and actually got back to about 115 pounds but since then I've lost it because I stopped eating that way. I don't know anything about SIBO except that it seems to involve the small intestine. If your stomach gurgles since starting miralax, you probably don't need it, or you should use the minimum. Start with 1/4 cap, add only if there's a problem with C. Unfortunately, I've become an expert at this and if only I could get off this junk and go back to normal life, but that's obviously never going to happen. The gut is tied to the brain. Serotonin actually exists in the bowels. So this disruption of bowel biome has further influenced for the worse my already horrifically poor thought process and feeling of hopelessness, pointlessness, and a really strong desire to never wake up one morning. Good thing I'm at an age where people drop dead. I hope you're able to resolve your problems.