Microbes reside everywhere in this world; in soil, in water, in air and in the flora and fauna. Bacteria dominate the microbial world, and live together with other microbes like fungi, parasites and viruses. They adapt their metabolism to to the local environment and contribute to the survival of the local ecosystem. They reside in “us” humans, on our skin, and inside our cavities. Resident microbes of the human gut are live in a “community” whose architecture and function is critical to our heath. These “commensal” bacterial community breakdown observed in several diseases and is termed “dysbiosis”. Whether the “dysbiosis” is causal to the disease or simply is an association observed in diseases is being investigated.