Lysozyme is an enzyme that is often referred to as the 'body's own antibiotic.' Lysozyme kills bacteria by breaking down the cell walls. This protein can be found in a number of body secretions such as tears and saliva. Alexander Fleming first discovered lysozymes, a natural protection system for the body. Lysozymes are too large to travel between cells however, they are present throughout the body where bacteria is likely to grow. In the blood, lysozymes provide some protection and combine with the immune system.