Probiotics have been used as a treatment method for more than a century. Probiotics are targeted for the prevention and treatment of a wide range of diseases and there is strong evidence for their effectiveness in some clinical conditions, and full understanding of their risks and benefits is needed. Probiotics are non-pathogenic microorganisms. Many of these microorganisms are part of the human flora of the intestine, they live in a synergistic relationship with gastrointestinal flora. Probiotics are used to treat gastro-intestinal and non-gastrointestinal diseases.