TG is a natural enzyme present in food materials, especially uncooked proteins, such as egg white, Tartar steak, sushi or oysters. Presently, CD patients are advised to avoid glutens, but not the above proteins. Thus, they are often exposed to naturally present TG, yet no side effects have ever been reported after ingestions of the above protein foods. Similarly, ACTIVA® preparations containing microbial TG have been marketed broadly in Europe for more than 15 years without any reported incidents of CD. These non-findings indicate that food-present TG does not contribute to the pathology of CD. Finally, a recent report by Gianfrani and colleagues (Gastroenterology. 2007: 133(3), 780-789) indicated that food-added microbial TG in the presence of an amine donor can actually decrease the immuno-stimulatory activity of gluten in CD patients.