http://www.nlm.nih.gov/medlineplus/druginfo/natural/894.html
Likely effective for... Preventing boron deficiency.
Boron seems to affect the way the body handles other minerals such as magnesium and phosphorus. It also seems to increase estrogen levels in older (post-menopausal) women and healthy men. Estrogen is thought to be helpful in maintaining healthy bones and mental function. Boric acid, a common form of boron, can kill yeast that cause vaginal infections.