Alterations in the gut and immune function are proposed to play an important role in the pathophysiology and progression of critical illness, especially in sepsis.1-6 Because the treatment of most aspects of critical illness is supportive, significant research efforts are focused on targeting and preventing the changes that occur in these two complex systems in efforts to devise new therapeutic options. This review focuses on the changes that take place in the gut and therapeutic interventions that may be available in the future.