In terms of surface area, the gastrointestinal tract comprises one of the largest organ systems in the body. The roles that it plays are varied and extend well beyond simply moving and digesting food to allow for the absorption of nutrients. In addition to acting as a barrier against the harsh external environment, the digestive system possesses an intricate lymph network responsible for ridding the body of waste and toxins. The gastrointestinal tract houses a highly complex ecosystem that contains trillions of microorganisms. Research continues to uncover new ways in which beneficial bacteria can positively impact health, expanding beyond the confines of the digestive tract.