Rue (ruda) has a long history of use in both medicine and magic, and is considered a protective herb in both disciplines. The hardy evergreen shrub is mentioned by writers from Pliny to Shakespeare and beyond, as an herb of remembrance, of warding and of healing. Early physicians considered rue an excellent protection against plagues and pestilence, and used it to ward off poisons and fleas. A Modern Herbal refers to the plant's disagreeable odor and flavor, but in truth, the bitterness of the leaves is only evident in large doses. In smaller amounts, it imparts a pleasant, musky flavor to cream cheeses and light meats. Rue was once believed to improve eyesight and creativity, and no less personages than Michelangelo and Leonardo Da Vinci regularly ate the small, trefoil leaves to increase their own. The legend of rue lives on in playing cards, where the symbol for the suit of clubs is said to be modeled on a leaf of rue. 

Rue has been used for centuries for both culinary and medicinal purposes, as well as in general use as a strewn herb to discourage pests. Small amounts of rue are often used in salads, egg dishes and cheeses in Mediterranean countries, and herbalists may prescribe it in low doses to help with a variety of gastro-intestinal ills. It is one of the most well-known of the magical protective herbs and is often used in spells of warding and protection in modern magic.