Stinging nettle, or Urtica dioica, is a perennial, flowering, stalk-like plant found in the United States, Canada, Asia, and Europe. It grows to a height of 2 to 4 feet, with its four-sided slender stems and leaves dark greyish green with serrated margins. Stinging nettle has a long medicinal history. In medieval Europe, it was used as a diuretic (to rid the body of excess water) and to treat joint pain. This diuretic activity has been the subject of a number of German studies. Animals fed stinging nettle showed increased excretion of chlorides and urea. The juice has a distinctly diuretic effect in patients with heart disorders or chronic venous insufficiency.