This course is intended for further in-depth study of the gastrointestinal physiology and immunology. Undergraduate students over forth year, and graduate students in medical-related studies are encouraged to take the course. The course is offered as two credits per school term. This course will focus on critical discussion of scientific papers in the field of gastrointestinal mucosal immunophysiology. Students will be graded by participation in class (15 %), reports (30 %), and presentations (50 %). The lymphoid tissues in the gastrointestinal tract contain the largest number of immune cells in the body, which is called gut-associated lymphoid tissue (GALT). The gastrointestinal tract serves as a first line defense system against potential pathogens and antigens in ingested foods. At the same time, the gastrointestinal tract has to provide oral tolerance to food proteins without developing an immune reaction against exogenous particles. The balance between tolerance and immunity in the gut plays a cruicial role in the pathogenesis of various gastrointestinal diseases.