Eyebright (Euphrasia officinalis) has a long history of traditional use in European herbal medicine for supporting eye health, particularly for conditions such as red, itchy, or inflamed eyes. Its use dates back to at least the Middle Ages, and it was a popular remedy among herbalists for various eye complaints, including conjunctivitis and eye strain. The name "eyebright" itself reflects this association, and it was even included in the doctrine of signatures, an old belief that a plant's appearance indicates its healing properties—eyebright’s flower markings were thought to resemble bloodshot eyes.

However, scientific evidence supporting eyebright’s effectiveness for eye conditions is extremely limited. While eyebright contains compounds such as flavonoids and iridoid glycosides that have anti-inflammatory and antioxidant properties in laboratory settings, there are no robust clinical trials confirming its safety or efficacy for treating red or itching eyes in humans. The available studies are either in vitro or animal studies, which cannot be directly extrapolated to human use. Major health agencies, such as the National Institutes of Health (NIH) and the European Medicines Agency (EMA), do not endorse eyebright for ophthalmic use due to the lack of clinical evidence and potential risk of contamination or irritation when used as eye drops.

In summary, eyebright’s use for eye complaints is justified by tradition, but scientific validation is lacking, and the quality of evidence is low.