Traditional use In the ancient Roman world, the naturalists
Pedanius Dioscorides and
Pliny the Elder recommended that rue be combined with the poisonous shrub
oleander to be drunk as an antidote to venomous snake bites. The refined oil of rue is an
emmenagogue and was cited by the Roman historian
Pliny the Elder and
Soranus as an
abortifacient (inducing abortion).
Culinary use Rue has a culinary use, but since it is bitter and gastric discomfort may be experienced by some individuals, it is used sparingly. Although used more extensively as a culinary herb in former times, it is not typically found in modern cuisine. Due to small amounts of toxins it contains, it must be used in small amounts, and should be avoided by pregnant women or people who have liver issues. It has a variety of other culinary uses: • It was used extensively in ancient Near Eastern and Roman cuisine (according to
Ibn Sayyar al-Warraq and
Apicius). • Rue is used as a traditional flavouring in Greece and other Mediterranean countries. • Used in
Old World beers as
flavouring ingredient. • The rue that is widespread in Ethiopian culture is a different species,
R. chalapensis.
Other Rue is also grown as an
ornamental plant, both as a low hedge and so the leaves can be used in
nosegays. Most cats dislike the smell of it, and it can, therefore, be used as a deterrent to them (see also
Plectranthus caninus). Caterpillars of some subspecies of the butterfly
Papilio machaon feed on rue, as well as other plants. The caterpillars of
Papilio xuthus also feed readily on it. It finds many household uses around the world as well. It is traditionally used in Central Asia as an insect repellent and room deodorizer. In premodern East Asia, bookmarks were made from rue in order to drive away
bookworms and insects. === Purported use against
evil === In Brazil, the
Ruta plant, known locally as
arruda, is believed to possess protective qualities against malevolent forces, particularly the
evil eye. The same tradition exists among
Sephardic Jews, who will often place it near vulnerable individuals, such as newborns, children, and mothers, to ward off evil. Among Sephardic Jews, beyond its symbolic significance, ruda is valued for its medicinal properties. When combined with
sugar, it is traditionally used to soothe eye discomfort and alleviate the symptoms of a mild cold. Additionally, inhaling ruda is thought to mitigate the effects of shock. Ruda's significance in Sephardic Jewish culture also extends to religious practices. During
Yom Kippur, a Jewish holiday marked by fasting, Sephardic synagogues often pass ruda among congregants to revitalise them. Other
Hasidim rely on the works of a famous Baghdadi
Kabbalist Yaakov Chaim Sofer who makes mention of the plant "ruda" () as an effective device against both black magic and the evil eye. ==Toxicity==