Chronic pancreatitis is characterized by foamy stools, clay-like stools and black stools. Chronic pancreatitis is a persistent damage to pancreatic tissue and function caused by various reasons. Chronic pancreatitis often leads to a decrease in the secretion of pancreatic lipase, and the enlarged head of the pancreas compresses the bile ducts, which often leads to upper gastrointestinal bleeding. 1. Decrease in pancreatic lipase secretion: chronic pancreatitis can lead to a decrease in pancreatic lipase secretion, which can lead to foamy stools or an oily surface, causing diarrhea and steatorrhea. 2. The enlarged pancreatic head compresses the bile ducts: the continuous enlargement of the pancreatic head can lead to obstructive jaundice, and then the stools will show the color of clay, also known as clay-like stools. 3. Upper gastrointestinal bleeding: If chronic pancreatitis is complicated by active bleeding in the upper gastrointestinal tract, the stools will be black, or even bloody in severe cases. 4. Abdominal pain: patients with chronic pancreatitis may experience abdominal pain, which is intermittent in the early stages and then persistent in the later stages.