Sucralfate is a biologically inert non-systemically acting compound. It requires polymerization for conversion into its biological active form, polymerized Sucralfate. Should this conversion occur in the body, using processes of the body to effect conversion subsequent to administering a dose, then the administered Sucralfate is a drug, as it enlists bodily functions to enact a chemical change. This form of Sucralfate should be regulated as drug. On the other hand, Sucralfate is manufactured as a polymerized product, requiring no bodily functions to enable its therapeutic effect, then this form of Sucralfate act as a medical device and should be regulated as such. This dichotomy of Sucralfate was first recognized by the US FDA in 2005 that subsequently cleared several polymerized Sucralfate barrier therapies as medical devices.This review covers the history of the regulatory dichotomy or duality of Sucralfate, the biological basis for Sucralfate clinical effects and the regulatory position of several barrier therapies.