St. John's wort (Hypericum perforatum L.) is a perennial herbaceous plant from the Clusiaceae family. It originates from Europe and Asia, and today it is widespread in all parts of the temperate and subtropical climate. It is recognizable by its double-edged stem, bright dots on the leaves and dark red juice that rubs out of the golden-yellow flowers. The healing properties of St. John's wort have been known since ancient times, and in folk medicine this plant species is used to treat various diseases. It contains bioactive substances such as hypericin, hyperforin and flavonoids. The antibacterial, antiviral and antifungal effects of St. John's wort preparations are known, and it is also used as an herbal antidepressant. The most famous preparation obtained from St. John's wort is St. John's wort oil, although the use of tea, tincture and balm has also been described. Hypericin can cause photosensitization, so sun exposure with St. John's wort is not recommended. This paper presents the systematics, morphology, cultivation, chemical composition, medicinal properties and use of St. John's wort.