Octreotide is a medication that has physicologic effects that inhibit glucagon, insulin, splanchnic blood flow, and vasoactive peptides in the gastrointestinal tract. It has been used for treatment of watery diarrhea from tumors that secrete vasoactive intestinal peptides. Octreotide has been studied for management of chemotherapy- and radiation-therapy-induced diarrhea. Octreotide is given by IV or subcutaneous injection.