Even the most devout Christian might be excused for not taking off time from his work or pleasures to celebrate on June 25 the birthday (not the gruesome beheading) of St. John the Baptist. This is also the day of the summer solstice (the longest day of the year) when the beautiful yellow St John’s wort flower begins to bloom. Wort, incidentally, derives from the Old English wyrt, simply meaning plant and going even further back to the older Germanic wurtiz, which evolved into the modern German wurzel meaning root. The flower itself has a long history, being traditionally gathered on St. John’s Day and piously soaked in olive oil for several days to produce an oily red preparation called the “blood of Christ”.

St. John’s wort was recommended by the Roman physicians Proscurides and Dioscorides in the first century AD. Its scientific name of Hypericum perforatum comes from the Greek hyperium. It was used since ancient times to protect humans against witches or demons, drive away spirits or ghosts, prevent evil diseases, and treat ailments ranging from snake bites to nervous disturbances, mainly by external applications in the form of oils. It was popular in the Middle Ages for a variety of complaints such as insanity.

Extracts of hypericum include more than fifty active ingredients: hypericin, pseudohypericin, hyperforin, tannin, flavonoids, xanthones, bioflavones, naphtodiantrones, and procyanidins. Hypericin, and to some extent hyperforin, are responsible for most of the clinical effects. Hypericum is available over the counter as a dietary supplement or promoted as a “natural” compound, sold as capsules, tablets, tinctures, or topical preparations, and still occasionally recommended for almost every illness known to man, for cuts, sprains, as a disinfectant, and to relieve inflammation and promote healing. Most of these indications are now no longer accepted as valid, with the possible exception of anxiety and mild depression.

Side effects of hypericum are common and may consist of dry mouth, dizziness, and fatigue. More serious side effects may arise because hypericum induces the P450 cytochrome system and affects the activity of liver enzymes, interacting with a wide range of medications such as oral contraceptives, anticoagulants, cyclosporin, and warfarin. It should not be taken during pregnancy, has caused intermenstrual bleeding, and may interact with other antidepressive drugs. The potency and purity of many preparations sold commercially cannot always be determined because they are not always prepared according to a particular specification.

Is St. John’s wort effective in the treatment of the many conditions it has been claimed to be? On the whole the scientific community remains skeptical because the results of most studies have been equivocal and unconvincing. At best, hypericum is more effective than placebo and equivalent to low doses of tricyclic antidepressants. Its history brings to mind the Tincture of Philosophers of great alchemist Paracelsus (1493–1541), claimed at the time to be widely effective even in small doses, so powerful that just as an invisible fire it consumed all diseases, even “leprosy, venereal disease, dropsy, the falling sickness, colic, cancer, fistulas, and the whole race of internal diseases more surely than one could believe.”

Further reading

• Klemow KM, Bartlow A, Crawford J, et al. Chapter 11: Medical Attributes of St. John’s Wort (Hypericum perforatum) in: Herbal Medicine: Biomolecular and Clinical Aspects, 2nd edition. 2011.
• Lawvere S and Mahoney M. St. John’s Wort. Am Family Physician 2005;72(11):2249.