Lactoferrin is a non-enzymatic secretory protein present in the acinar cells of human pancreas, and specifically increased in the pancreatic juice of chronic calcifying pancreatitis patients. Immunocytochemical localization of lactoferrin demonstrates its presence in the zymogen granules of the pancreatic acinar cell as well as in the endoplasmic reticulum cisternae. On the same section, only a few acini are positive but all cells within individual acini are similarly either positive or negative. The intensity of the reaction and the number of stained acini are greater in chronic calcifying pancreatitis patients.