Most people don't like to cry and avoid extraneous body fluids whenever possible. But new evidence shows that our own tears, salvia and other fluids contain key anti-bacterial agents. Msnbc.com reports that lysozyme, an enzyme found in human tears and other biological fluids, fights invading bacteria as strong as anthrax.

Lysozyme is present in human milk, tears, semen, mucus and saliva. It is also found in egg whites. It attacks the cell walls of bacteria, ultimately breaking it down. The anti-bacterial characteristics of lysozyme were first observed in 1922 by Alexander Fleming, who discovered penicillin. It is considered a natural form of protection from pathogens such as E.coli and salmonella.

New evidence shows that it can defend against anthrax as well. Saeed Khan is a researcher at the National Center for Toxicological Research in Arkansas. Kahn and his team infected eggs whites with an anthrax substitute. They found that the lysozyme in the egg whites killed the spores. Lysozyme also destroyed spores in beef and milk.

Alexander M. Cole is an associate professor at the Burnett School of Biomedical Sciences at the University of Central Florida. As he told Msnbc.com, "Pretty much every wet area of your body has antimicrobial powers.” Semen contains peptides that kill bacteria to make way for sperm. Mucus can kill germs. And even human urine can be anti-microbial.

As Cole tells Msnbc.com, “there is evidence that it [human urine] contains a peptide called human beta defensin 1 that may help keep a urinary tract infection from reaching the kidneys.” Experts hope that lysozyme may be developed into a vaccine against biological weapons and more.

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