The intestinal microbes of any region of the gut can substantially influence the health state and development or progression of diseases. These microbes regulate homeostasis and metabolism, in part, through their beneficial activities on intestinal and distant histohematological barrier and permeability, immune system functions, gut motility,
absorption of nutrients, and synthesis of microbial-derived beneficial bioactive molecules.Though the gut microbiota has a huge beneficial role, it can become potentially harmful, especially under unfavorable conditions of the intestinal microenvironment, possibly resulting from unhealthy diet and nutrition, antibiotic administration, or pathogenic invasion. The harmful effects of the intestinal microbiota are due to its abnormal behavior, characterized by the presence of pathogenic microbes or a substantial reduction in the proportion of the intestinal beneficial microbes.
