The human gastrointestinal tract is not only responsible for the processing and digestion of food, but also for immune defense. Studies have shown that intestinal microbes play a crucial role in the imprinting and maturation of the immune system. Impaired or disturbed immune systems can cause inflammatory processes, food allergies, autoimmune gastritis as well as chronic inflammatory bowel disease. Based on a literary research, this diploma thesis discusses the influence of antibiotics on the intestinal microbiome. Antibiotics work against infectious bacteria. Different antibiotic substances act according to various mechanisms of action and have therefore a broad spectrum of activity, however, all do work bacteriostatic and/or bactericide. A broad-spectrum antibiotic bears the risk of destroying all germs, including the ones responsible for a regular and unproblematic digestion. Further, the physical and psychological well-being could be affected negatively. In addition this diploma thesis discusses on recent studies and compares research results regarding the meaningfulness of probiotics intake.