View photos of the medicinal plant Equisetum arvense (Horsetail), profiled in Medicinal Plants of the Western Mountain States and Herbal Medicine: Trends and Traditions.

A passage from Herbal Medicine: Trends and Traditions:

Mainly a urinary tract medicine, Horsetail is soothing to the area and is of use in diminishing urinary tract irritability and painful urination. Internal preparations are mildly diuretic and will assist in eliminating fluid build up (from non–organic causes) around the ankles, wrists, and mid–sections of the body. Moreover, when taken as a daily tea, kidney stone formation is reduced through the plant’s ability of increasing urine volume.