Many pancreatic cancer patients experience diarrhea, constipation or both. Diarrhea consisting of loose, watery, oily or foul-smelling stools can be caused by insufficient amounts of pancreatic enzymes in the intestines. This leads to malabsorption as undigested food passes quickly through the digestive tract. Constipation is also a common problem, particularly in patients taking pain medications. These medications slow the passage of food through the intestines. If the digestive system works too slowly, it can cause stools to become dry, hard and difficult to pass.