Rami, There is good and bad bacteria in the the GI tract and stomach. The antiobiotics do not know good from bad, so it kills all the bacteria.What I suggest is getting some acidophilus. Megadophilus, acidophilus capsules can be bought in a health store, or some grocery stores. They would be in the refrigerated area. Yogurt has acidophilus, but not really enough to help you. Also sugars can deplete the acidophilus ,so flavored yogurt will sort of be cancelled for its effect.Joanne luckylungsforjo@aol.com