Zauberwurzel. The traditional German folk name for the mandrake root. This poisonous herb is historically used in folk magic for protection, fertility and prosperity.
Whole mandrake placed above the mantel or on the head of the bed will protect against evil and negative energies. The whole root is also used as a poppet in sympathetic magic.
Small pieces of the root mixed with various other herbs are used in sachets to protect against headaches, aid in sleep and increase fertility in men and women. Mandrake is representative of earth and is ruled over by Hecate and Hathor.
Never use mandrake in anything intended for ingestion as it is highly poisonous.

Dried mandrake can be reconstituted in a dish of water, and the left over water then sprinkled at the doors and windows of your house for protection.
Legend says that when pulled from the ground, mandrake emits a deadly scream. Thus harvesting instructions are rather complex and involve the sacrifice of one’s dog.
If growing your own mandrake, be sure to plant at the waning of the moon to increase the power and strength of the plant’s roots.
If true mandrake is out of your price range or difficult to find locally, the roots of bryony and ash make a good substitute. That said, be sure to learn all of a plant’s properties whenever making substitutions.
Further information and recipes can be found in Magical Herbalism
and the Encyclopedia of Magical Herbs
by Scott Cunningham.