Herb reference
Ruta graveolens
Crystalis is a reference resource for herbal, crystal, and somatic practice.
This library is designed to help readers orient, compare, and research. It is not a substitute for medical care or practitioner judgment.
Botanical / meta
Rue is a bushy, evergreen subshrub reaching 50–100 cm in height, with distinctive blue-green, pinnately compound leaves divided into rounded, lobed leaflets that emit a powerful, pungent, somewhat unpleasant aroma when crushed. The small, bright yellow, four-petaled flowers with fringed edges appear in dense, flat-topped corymbs from June to September. The fruit is a dry, four-lobed capsule containing numerous black seeds.
Rue contains furocoumarins (psoralens) — primarily bergapten (5-methoxypsoralen) and xanthotoxin (8-methoxypsoralen) — responsible for severe phototoxicity. Also contains quinoline alkaloids including graveoline, skimmianine, and kokusaginine; volatile oils including methyl nonyl ketone (2-undecanone), methyl heptyl ketone; flavonoids (rutin, quercetin); and hydroxycinnamic acids. The furocoumarin content is highest in leaves and during flowering.
The practical read
Rue contains furocoumarins (psoralens) — primarily bergapten (5-methoxypsoralen) and xanthotoxin (8-methoxypsoralen) — responsible for severe phototoxicity. Also contains quinoline alkaloids including graveoline, skimmianine, and kokusaginine; volatile oils including methyl nonyl ketone (2-undecanone), methyl heptyl ketone; flavonoids (rutin, quercetin); and hydroxycinnamic acids. The furocoumarin content is highest in leaves and during flowering.
Route panel
Evidence and safety may differ by preparation. Essential oil, tea, tincture, extract, infused oil, and topical use are not interchangeable.
Quality
Prefers poor, well-drained, alkaline soil in full sun — thrives in hot, dry conditions. Drought-tolerant once established. Seeds germinate irregularly; soak in warm water before sowing. Space 45–60 cm apart. Prune hard in spring to maintain bushy habit. Protect from excessive winter moisture. All parts have a strong, persistent odor; plant away from living areas.
Leaves are the primary part used, harvested before flowering when furocoumarin content is moderate. Dried leaves lose volatile oil but retain furocoumarins. Oil is extremely concentrated and dangerous — not for home use. Available dried, as homeopathic preparations (highly diluted, externally only), and rarely as tincture. Quality markers: blue-green color, strong pungent aroma. Must be stored away from light to minimize furocoumarin degradation.
Companion
Crystal side
The deeper layer
Clinical and compound notes are included as a research layer, not as treatment instructions.
HIGH RISK — SEVERE PHOTOTOXICITY AND ABORTIFACIENT. Rue contains furocoumarins (psoralens) that cause severe phytophotodermatitis — skin contact followed by sun or UV exposure produces blistering burns, hyperpigmentation, and long-lasting skin damage. Wear gloves when handling; avoid all skin contact and subsequent sun exposure. ABORTIFACIENT — rue stimulates uterine contractions and has been historically used to induce abortion. Absolutely contraindicated in pregnancy and breastfeeding; may cause uterine hemorrhage, abortion, and fetal harm. All parts of the plant are toxic if ingested in medicinal quantities — ingestion causes vomiting, diarrhea, epigastric pain, hypotension, bradycardia, seizures, hepatic and renal impairment, and death in severe cases. Neurotoxic effects include tremors and seizures. Contraindicated in kidney disease, liver disease, and seizure disorders. Internal use should only be under direct supervision of a qualified healthcare professional. Keep away from children.
Questions
Rue is high risk on two fronts. Its furocoumarins (psoralens), chiefly bergapten (5-methoxypsoralen) and xanthotoxin (8-methoxypsoralen), cause severe phytophotodermatitis: skin contact followed by sun or UV exposure produces blistering burns, long-lasting hyperpigmentation, and lasting skin damage, so gloves are essential and skin contact with subsequent sun must be avoided. Rue is also a potent abortifacient that stimulates uterine contractions and is absolutely contraindicated in pregnancy and breastfeeding, with risk of uterine hemorrhage, abortion, and fetal harm. Ingestion in medicinal quantities is toxic, causing vomiting, diarrhea, epigastric pain, hypotension, bradycardia, seizures, and hepatic and renal impairment, with death in severe cases. It is contraindicated in kidney disease, liver disease, and seizure disorders, and internal use should only occur under direct professional supervision.
Because all parts of rue are toxic in medicinal quantities and the furocoumarin content is highest in the leaves and during flowering, there is no safe self-directed internal dose, and any internal use belongs strictly under a qualified practitioner. When handling the fresh plant for gardening or harvest, wear gloves, cover skin, and avoid sun exposure afterward to prevent phytophotodermatitis. Historically it was used in very small amounts as a bitter and emmenagogue, but its narrow margin between effect and toxicity makes lay dosing dangerous. It should be kept away from children, and the essential oil in particular is hazardous.
Rue is a woody-based perennial in the family Rutaceae with distinctive blue-green, rounded, lobed leaves and an intensely bitter, acrid, musky odor that many find unpleasant. Quality dried material retains that strong characteristic scent and a grey-green color, since loss of aroma indicates degraded volatile oil, including the methyl nonyl ketone (2-undecanone) that dominates its smell. Even well-preserved, aromatic material remains toxic, so quality assessment is about correct identification and handling rather than safety for use. Its furocoumarin and quinoline alkaloid content (graveoline, skimmianine, kokusaginine) make confident botanical identification essential before any contact.
Rue belongs to the Rutaceae and shares the phototoxic psoralens bergapten and xanthotoxin with plants such as giant hogweed, wild parsnip, and citrus rind, all of which can cause phytophotodermatitis. What distinguishes rue is its additional load of quinoline alkaloids (graveoline, skimmianine, kokusaginine) and its strong abortifacient and neurotoxic potential, making it more systemically dangerous than many other psoralen-bearing plants. Its volatile ketones, including methyl nonyl ketone, also give it a uniquely acrid odor. This combination of phototoxicity, abortifacient action, and hepato-renal and neurotoxicity is why rue carries stronger contraindications than most furocoumarin plants used decoratively or culinarily.
Dried rue should be stored in a clearly labeled, airtight container kept well away from children, pets, and food, reflecting its toxic status rather than ordinary culinary handling. Like other aromatic herbs it loses volatile oil over roughly a year, marked by fading of its characteristic acrid odor, but degradation does not make it safe, since the furocoumarins and alkaloids persist. Keep it out of light, heat, and humidity to limit mold. Anyone handling stored rue should still avoid skin contact and subsequent sun exposure because the phototoxic psoralens remain active in dried material.
Sources & Citations
Peer-reviewed sources for the pharmacological and clinical claims on this page. Crystalis herb entries describe tradition and current research; they are reference, not medical advice.
SAFETY
Resource framing
Crystalis is a reference resource for herbal, crystal, and somatic practice.
This library is designed to help readers orient, compare, and research. It is not a substitute for medical care or practitioner judgment.
Clinical and compound notes are included as a research layer, not as treatment instructions.
Evidence and safety may differ by preparation. Essential oil, tea, tincture, extract, infused oil, and topical use are not interchangeable.