Gut bacteria are an important part of the human gut's microbiota ecosystem, which is populated by 1014 microorganisms, ten times more than human cells. Gut bacteria play a crucial role in human health, giving necessary nutrients, manufacturing vitamin K, assisting with cellulose digestion, and stimulating angiogenesis and enteric nerve activity, among other things. Intestinal infections cause a lot of morbidity and mortality all around the world. Probiotics are increasingly being utilised to treat a variety of medical disorders, including allergic diseases (atopic dermatitis, perhaps allergic rhinitis), bacterial vaginosis, urinary tract infections, and dental caries or respiratory infections prevention. Probiotics are used to treat a wide range of gastrointestinal (GI) conditions. The gastrointestinal system serves as a vital link between the host and the outside world. It is populated by approximately 10 trillion microorganisms of various types weighing 1–2 kilograms.