Abstract
Probiotics are those microorganisms that are incapable of causing any disease and when consumed, they impact the host positively. Treatment of GIT infections with antibiotics can affect this microflora of GIT which leads to several complications such as different colorectal cancers, constipation, allergic reactions and others. Thus, the addition of these useful bacterial species to the GIT may be an effective method to prevent such disease and also to restore the microbial equilibrium. Mostly used bacterial genera in the preparation of probiotics are Escherichia, Bacillus, Streptococcus, Bifidobacterium, Lactobacillus, Bifidobacterium and Enterococcus. Moreover, few strains of fungi belonging to Saccharomyces are utilized in probiotics preparation. In this review, we tried to assess the significance of probiotics in the gastrointestinal tract and also studied their adverse effects.