Mandrake

from here:

"Atropa Mandragora
considered an anodyne and soporific the early Anglo-Saxons used mandrake as a component of exorcism, however, in large doses it is said to cause delirium and madness. It is also used as a protective charm for the home. It was used to increase fertility in women, and would be carried to increase courage.
The leaves are quite harmless and cooling, and have been used for ointments and other external application, it was used to help those in pain to sleep. However the plant is also quite poisonous and not to be meddled with.
The roots of Mandrake, where the most power lies, were supposed to bear a resemblance to the human form, on account of their habit of forking into two and shooting on each side. In the old Herbals we find them frequently figured as a male with a long beard, and a female with a very bushy head of hair. It was believed to be very dangerous to dig up the root, which apparently groaned and shrieked as you did so. To hear this was supposed to be fatal. "