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Probiotics are living microorganisms that are mostly from the family of Lactobacillus and Bifidobacterium bacteria. These microorganisms contribute to the health of the host through various mechanisms such as the production of antimicrobial substances, various inhibitors and competition with pathogenic agents. Although some of the mechanisms of probiotics have not been fully determined, its effect on the prevention and treatment of many diseases such as digestive problems, infections and even cancer has been proven. In addition to the direct effects of probiotics in the field of health, the use of these microorganisms in the field of industry also indirectly affects human health. Therefore, the purpose of this review article is to introduce probiotics and some of their roles in the fields of medicine and industry in improving human health.