Lysozyme (muramidase) is a protein with a molecular weight of approx. 15 kD and belongs to the group of alkaline glycosidases. Lysozyme is made by granulocytes, monocytes and macrophages. The main source for faecal Lysozyme are the intestinal granulocytes. Lysozyme can be detected in all cells of the inflammatory infiltrate during an acute attack of Crohn‘s disease. To some extent, Lysozyme is also secreted actively by mononuclear cells into the bowel lumen.