Horsetail (Equisetum arvense). Horsetail is strongly astringent and is therefore used for both internal and external wounds. It has been used for centuries, as a diuretic aid for kidney infections, dropsy, and gravel. It also is beneficial as an eyewash for swelling eyelids and is good for preventing split-ends. It’s known to kill parasites and dissolve tumors. Horsetail contains a large amount of silica, helping make fingernails stronger; it increases the flow of urine; and helps hold calcium in the body, indeed, it helps facilitate the use of calcium by the body. Studies have shown that fractured bones will heal much faster when Horsetail is taken. It is also used as a poultice to reduce menstrual bleeding; it is effective because it promotes coagulation, hence, decreases bleeding.