Proprietary Pre & Probiotic Blend With Enzymes, Live Yeast Culture, Beta Glucan & Electrolytes The intestines are the largest component of the immune system in the body, making up approximately 70% of the total immune system. The mucosal barrier in the intestines helps to block the entrance of most pahtogenic bacteria into the body while allowing the entrance of permeable nutrients. Because most pathogens enter the body through the mouth and then the intestinal tract, these intestinal defenses must be working optimally to cope with the onslaught of foreign substances and pathogens to which the intesines are constantly exposed.