FYI
"Goat's rue, French lilac, Italian fitch, and professor weed are all names for the same plant:
Galega officinalis. This perennial herb, 3 feet tall and with purple, blue, or white flowers, was used in folk medicine to treat diabetes starting in the Middle Ages, maybe earlier. Though it gave rise to metformin, one of the most popular diabetes medications in the world,
G. officinalis is now widely considered poisonous. In the early 20th century, researchers isolated a compound from
G. officinalis called guanidine, which could lower blood glucose levels in animals but was also toxic. Chemists found that they could make the compound more tolerable by bonding two guanidines together, forming a biguanide. Metformin is one such biguanide, first synthesized in 1929 and then clinically developed in the late 1950s by the French physician Jean Sterne, who gave it its first trade name, Glucophage ("glucose eater")."
http://www.diabetesforecast.org/2010/dec/the-origins-of-metformin.html