Understanding the role of the microbiota in the development and progression of diseases has received a great deal of attention in recent years. The microbiota is defined as the group of microorganisms, such as bacteria, which normally inhabit the human body. These microorganisms, also known as microflora, are composed of a variety of species of bacteria, each having a different function, and there are some bacteria whose functions remain unknown. Several studies have shown that patients with inflammatory bowel diseases, such as Crohn's Disease, have a microbiota composition that is different from healthy individuals, suggesting that certain species of bacteria might be important in causing some common gut inflammatory disorders. Dr. Navkiran Gill is investigating how the human immune system regulates the microbiota and how our microbiota may direct our immune responses to various pathogens. Specifically, she is doing a series of experiments involving antibiotic use in specially bred mice infected with Salmonella. The results will provide important information regarding the effect of antibiotics on the microflora, and allow her to correlate changes in our microflora to changes in our ability to mount an immune response against a pathogen such as Salmonella. The results of Dr. Gill’s research will provide information that may be used to design new therapeutics that take into consideration the important role of our microflora.