Intestinal transcellular calcium pathway comprises three steps that should be highly regulated. The role of sulfhydryl groups from different membrane proteins and the intestinal glutathione levels will be analyzed in relation with the Ca²⁺ movements across those three sites of the enterocytes. Special attention will be focused on the effect of menadione, acetaminophen and DL-buthionine-S,R-sulfoximine,  all drugs that produce oxidative stress, on the intestinal calcium absorption and the activity of proteins presumably involved in this process, e.g. plasma membrane Ca-ATPase and alkaline phosphatase. Redox changes produced by those drugs on mature enterocytes will also be described. Finally, pharmacological implications related to the use of those oxidants on intestinal function will be discussed.