St. John’s Wort (hypericum perforatum) is widely occurring on Lesvos and is much used for its medicinal properties. It is usually used as an infusion of its dried flowers in olive oil which, after exposure to the sun, turns a deep red colour. Known as balsam (βάλσαμο) it can be taken internally as a sedative or antidepressant and for the treatment of duodenal ulcers. It is often applied externally to treat wounds, ulcers, rheumatism, sunburn, etc.
Active constituents include hypericin, which shows antibiotic and antiviral activity, and hyperforin which has antidepressant properties.
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