Antibiotics can upset the balance of intestinal flora and this can result in unpleasant stomach upsets. Gefilus lactic acid bacteria products balance gastrointestinal bacteria and improve the well-being of the stomach during a course of antibiotics. Gefilus products should always be taken during a course of antibiotics and afterwards. Gefilus and the antibiotics should not be taken at the same time, so leave a gap of 2-3 hours in between.