During the late unpleasantness between the South and the Yankees, the Niter Board of the Confederacy requested that Southern women save their "chamber-lye" for the making of niter. The old urine (which is what "chamber-lye" or "chamber-ley" is) would be collected and taken to a powder mill to be turned into gunpowder to shoot Northern troops.

Nothing special about the urine, just that the men were off in Army and the women were at home, patriotically mictruating for victory.

(By the way, the book Foxfire 5 has a nice section on how to make your own gunpowder. One of the ingredients is urine, the older and staler the better.)