Antibiotics destroy the *good* bacteria in the gut, along with the bad bacteria they're prescribed for. As long as you're not lactose intolerant, you might look into taking capsules or powdered Lactobacillus Acidophilus (and/or other "good" bacteria, aka "biotics") next time you're on a round of antibiotics, or whenever. You can get these usually at a health-food store. (I think there may be Lactobacillus products that have no lactose in them, not sure). The depletion of the good gut bacteria by antibiotics can set you up for diarrhea etc., you kinda need to replenish them in your gut. Even eating plain yogurt that has live lactobacillus can be helpful, again as long as you have no problems with dairy products.