Hi Joan! I have a pretty extensive list of medications that can either trigger an insulin response or increase insulin resistance, but I don't see any antibiotics listed here. That's not to say they won't...I don't know. But I do think that any illness can alter your body's response to insulin, because it is a stress to your system. As bad as we hate to have to take antibiotics, sometimes they are a necessary evil. As far as the yeast infection is concerned, of course yogurt with live cultures is the best prevention, but there is nothing LC about yogurt. I would suggest that you find a reputable natural food store and ask for a probiotic ( like acidophilus/bifidus). These are capsules, usually, or tablets (sometimes in a liquid, but beware of what they use to make the liquid palatable!) that contain the needed flora that the antibioitics have killed off. They're not terribly expensive and can sure prevent a very uncomfortable yeast infection! Hope this helps, and I hope you feel better right away!!