Eyebright (mainly Euphrasia rostkoviana and E. stricta [syn. E. officinalis], Orobanchaceae) is a semi-parasitic alpine plant that has recorded uses in Europe that date back to the early 14th century. Its common name comes from its long history of use in the treatment of conjunctivitis, sties, and other ailments of the eye. Eyebright flower, leaf, and stem were used in poultices or as a tea for inflammatory conditions such as fever, cough, sore throat, and earache.¹ In the 16th century, it became a popular flavoring for alcoholic beverages such as beer and wine. Research has shown that compounds in eyebright essential oil have antimicrobial properties, as well as tonic and astringent qualities.²

References

1. Committee on Herbal Medicinal Products. Assessment report on Euphrasia officinalis L. and Euphrasia rostkoviana Hayne, herba. London, UK: European Medicines Agency; September 16, 2010.
2. Novy P, Davidova H, Serrano-Rojero CS, Rondevaldova J, Pulkrabek J, Kokoska L. Composition and antimicrobial activity of Euphrasia rostkoviana Hayne essential oil. Evid Based Complement Alternat Med. 2015;2015:734101. doi:10.1155/2015/734101.