Probiotics are usually defined as live microbial food ingredients beneficial to health which comprise of normal commensally bacteria as a part of the healthy human gut micro flora. The gut microflora is an important component of the gut defense barrier and have been shown to induce and maintain oral tolerance in experimental animal models. Functional foods, including probiotic bacteria, are an attractive medium for maintaining the steady nutritional state of the host with defective gut barrier functions. The gut-associated lymphoid tissue (GALT) embraces a crucial component of the total immunological capacity of the host in recognizing and selectively handling alien antigens for the initiation of immune responses. Normalization of increased intestinal permeability and altered gut micro ecology can ensure improvement of the function of the gut barrier. Probiotics do modify the composition of the gut microflora and, as a consequence, they have been shown to influence both intestinal and body functions. This review also discussed some patent related to the field.