Rue has a long history of use as a domestic remedy, being especially valued for its strengthening action on the eyes. The plant contains flavonoids (notably rutin) that reduce capillary fragility, which might explain the plant's reputation as an eye strengthener. Some caution is advised in its use internally, however, since in large doses it is toxic and it can also cause miscarriages. The whole herb is abortifacient, anthelmintic, antidote, antispasmodic, carminative, emetic, emmenagogue, expectorant, haemostatic, ophthalmic, rubefacient, strongly stimulant, mildly stomachic, and uterotonic. The tops of fresh shoots are the most active medicinally, they should be gathered before the plant flowers and can be used fresh or dried. An infusion is used in the treatment of hysterical affections, coughs, flatulence, etc. The juice of the plant has been used in treating earaches and chewing a leaf or two is said to quickly bring relief from giddiness, nervous headaches, palpitations, etc. An alkaloid found in the plant is abortifacient, anti-inflammatory and antispasmodic. A homeopathic remedy is obtained from the fresh herb, harvested in early summer shortly before flowering begins. This is used in the treatment of a variety of complaints including eye strain, headache, and sprains.
