Eyebright (Euphrasia officinalis), also known as euphrasia or meadow eyebright, is a flowering herb found primarily in eastern European countries such as Hungary and Yugoslavia. Eyebright gets its name from the red streaks found on its flowers, which suggest the appearance of bloodshot eyes. Medieval physicians used a philosophy called the Doctrine of Signatures in order to determine which herbs would best address certain ailments. The eyebright plant was considered to be a natural curative for eye problems such as conjunctivitis, blepharitis, dry eye and sties.

The use of eyebright as an alternative treatment for eye diseases is still controversial, and as of this date the FDA has not approved its use for external eye problems. Even physicians and herbalists familiar with eyebright discourage the use of non-sterile homemade decoctions of eyebright, preferring that patients only use sterile eyebright solutions available as an imported item in health food stores and other herbal medicine outlets. Users generally put several drops of eyebright solution on a sterile cloth and apply it as a compress directly to the affected eye.

Although there is little scientific information on the effectiveness of eyebright, it is believed that the plant contains tannins, which would work as natural astringents if placed in the eyes. Other components of eyebright may have mild antibacterial properties, as well. Eyebright should never be applied directly to a person's eyes if he or she wears contact lenses or has had recent eye surgery for vision correction or cornea treatments.

Eyebright can also be consumed as a tea several times a day, purportedly to address sinus problems and coughs associated with the common cold. Eyebright tea may also help with hoarseness and sore throat, although there is little evidence to support this claim. Some patients believe eyebright tea can also address nausea and respiratory problems in general.

The use of eyebright is generally discouraged by mainstream doctors because it can cause serious damage to the user's eyes if not properly prepared and sterilized. Even when used correctly, eyebright can cause significant eye redness and itching, especially if applied directly to the surface of the eyes. Internal ingestion of eyebright tea appears to be safe, although the effects of the herb on pregnant or nursing women have not been fully studied.