Vasoactive Intestinal Polypeptide is a poorly-understood hormone secreted by the pancreas. Its function is really unclear. Its clinical importance is in that a person can develop a neuroendocrine tumor of the pancreas that secretes vasoactive intestinal polypeptide. This is not a regular pancreatic cancer and it is exceedingly rare. If it does happen, patients experience massive diarrhea. In fact, one of the names for this syndrome is "pancreatic cholera". It is also known as a VIPoma or WDHA syndrome. WDHA stands for Watery Diarrhea, Hypokalemia and Achlorhydria. Treatment would be resection if possible and if not some patients respond to a medicine called octreotide.