The human microbiome is composed of bacteria, archaea, viruses and eukaryotic microbes that reside in and on our bodies. These microbes have tremendous potential to impact our physiology, both in health and in disease. The gut microbiome, which hosts up to 1000 bacterial species that encode about 5 million genes, perform many of the functions required for host physiology and survival. The gut microbiota in humans evolve throughout life and appear to play a pivotal role in both health and disease. Most of us are aware that the bacteria in our gut play an important role in digestion. In addition, gut bacteria are known to aid the production of certain vitamins such as vitamins B,K and play a major role in immune function. the most studied is how gut microbiota affects an individual's risk of obesity, heart disease, rheumatoid arthritis, Fatty liver disease, cirrhosis, liver cancer, and other metabolic conditions. Microbiota in gastrointestinal tract such as found that the persons have microorganisms in the stomach (Helicobacter pylori) possible risk to peptic ulcer disease, tumors and cancer in the stomach more than person who do not find this type of bacteria. Two thirds of the gut microbiome is unique to each person, and what makes this unique is the food we eat, the air we breathe and other environmental factors. Some studies have even suggested the gut microbiome is influenced by genes.