St. John's Wort

Hypericum perforatum is the herb medieval surgeons packed into deep wounds, the herb that Midsummer bonfires were fed to drive out demons, and the herb that triggered organ-rejection crises in transplant patients when it turned out to interact with cyclosporine. Three stories, one plant — and they need to be kept separate.

The plant

Hypericum perforatum is a perennial of roadsides and dry meadows, native across Europe and western Asia and now naturalized in North and South America, Australia, and beyond. It stands thirty to ninety centimetres tall on branched, two-ridged stems. The flowers are five-petalled, bright yellow, with a dense brush of stamens; when you crush a bud, it bleeds a red-purple oil. Hold a leaf to the light and the surface appears perforated — dotted with translucent oil glands. The species name perforatum comes from exactly this: the pinhole appearance that medieval herbalists read as a divine signature, the plant pierced with light.

Flowering peaks in late June. That timing is not incidental to the plant’s entire cultural history.

What the names carry

The genus name Hypericum is from the Greek hyper eikon — “over an apparition” or “above an icon.” Some authorities interpret this as a reference to the plant’s use against supernatural agents, while others derive it from the practice of placing a sprig of St. John’s wort above an icon in the house for protective purposes. Both readings are probably correct as folk etymology: the name accrued both meanings over centuries of use.

The specific folk name that follows the herb everywhere is fuga daemonum, “demon’s flight” or “chase-devil.” An old Scottish name, “The Deil Chaser,” reflects the same idea — an Anglo-Saxon belief that the plant protected people from the Devil. There is, however, a limit to how far back this name honestly runs. Classical writers — Dioscorides, Pliny, and Theophrastus — do not mention either fuga daemonum or the apotropaic use; it is herbalists from the sixteenth and seventeenth centuries who commonly record the name. The protective reputation is medieval and early-modern, not antique. That is still a very old reputation. It simply is not the one sometimes claimed.

The species name perforatum refers to the flowers and leaves, which look as if they have been perforated with needles. Medieval herbalists also called the plant Corona regia — “royal crown” — because its flowers resemble a solar corona.

Gathered on St John’s Eve

The feast of St John the Baptist falls on 24 June, a date that has tracked the summer solstice in the European calendar since the Christianization of Midsummer fire customs. Hypericum perforatum flowers at its peak exactly then. The form and colour of its flowers recalled the sun, and with Christianization, the solstice and its plants were dedicated to John the Baptist. In folk legend, the plant’s red juice symbolizes the blood of the martyr John.

The botanical name of the genus preserves its ancient use as a fuga daemonum, or devil chaser. When crushed, the flower buds yield a watery, purplish-red liquid, associated with the blood of the beheaded Saint John the Baptist, whose birth was celebrated on June 24.

The practical apotropaic customs around this gathering are documented from the early modern period across northern and western Europe. One belief was that bringing the flowers of St. John’s wort into the house on a Midsummer Eve would protect one from the evil eye, banish witches, promote good fortune and protect the house from fire. In one case in 1696, Aubrey tells the story of a poltergeist bothering the occupants of a house in London — and St. John’s wort among the counter-measures deployed. The customs of throwing the herb into the solstice bonfire and hanging bundles above doors and windows recur across British, German, Scandinavian, and Low Country sources.

While St. John’s wort warded off witches and ill fortune at midsummer, it was employed as a medicinal herb at other times; the Hortus Sanitatis recommends its use to stanch bleeding, bind wounds, join cut sinews, and counteract the thrusts of poisoned weapons.

The wound herb

From at least the late medieval period, Hypericum held its strongest medical reputation as a wound herb. John Gerard suggested boiling the flowers and seeds and drinking the mixture to guard against bladder stones. He also recommends its leaves for use on burns, scalds, and other wounds. Gerard also gives a recipe for making St John’s Blood — crushing the leaves, flowers, and seeds and putting the mixture into a glass bottle with olive oil, before leaving it in the sun for a few weeks. The resulting red oil, in Gerard’s words, was “a most precious remedy for deep wounds” and wounds “made with a venomed weapon.”

Sixteenth-century herbalists including Paracelsus, Gerard, and Culpeper all recommended St. John’s wort preparations to treat wounds and alleviate pain. In 1525, Paracelsus recommended it for treating depression, melancholy, and overexcitation. His exact phrasing — “God has placed a great arcanum in the herb, just for the spirits and mad fantasies that drive people to despair” — straddles the line between spiritual and physiological explanation in a way characteristic of his era. It is not the same as a clinical claim, but it is early documentation of the plant being associated with mental distress, which is worth noting.

St. John’s wort’s use as a medicinal herb continued in Europe, spreading to other continents between the eighteenth and nineteenth centuries. It was commonly made into teas and tinctures for treatment of anxiety, depression, insomnia, water retention, and gastritis.

The antidepressant question

The contemporary clinical use of Hypericum is for mild to moderate depression, and this is one of the more robustly studied herbal medicines in the pharmacological literature. The two active constituents of main interest are hypericin (a naphthodianthrone responsible for photosensitizing effects) and hyperforin (a lipophilic phloroglucinol responsible for most of the drug interactions and likely much of the antidepressant activity). European pharmaceutical companies produce standardized formulations; these are prescribed by medical doctors in Germany and other countries and have been for decades.

What the clinical evidence supports is a meaningful effect in mild-to-moderate depression compared with placebo, with a side-effect profile generally more tolerable than synthetic antidepressants at equivalent doses. What it does not support is equivalence for severe depression, and the drug-interaction profile (see below) substantially constrains who can safely use it.

For practice: the infused oil that Gerard documents — crushed flowers steeped in olive oil until the oil runs red — remains an active preparation used in folk herbalism for bruises, nerve pain, and minor burns. This is topical use, which carries lower interaction risk than oral preparations, though photosensitivity remains relevant to skin exposed after treatment.

Safety: photosensitivity and drug interactions

This section is not optional reading.

Photosensitivity. Hypericin is a photosensitizer. Fair-skinned people and those handling fresh plant material in sunlight can develop phototoxic skin reactions. The effect is dose-dependent and more pronounced with internal preparations than topical ones, but both warrant caution.

CYP3A4 induction. This is the serious one. Preparations of St. John’s wort are potent activators of pregnane-X-receptor (PXR) and hence inducers of cytochrome P450 enzymes — most importantly CYP3A4 — and P-glycoprotein. The degree of CYP3A4 induction correlates significantly with the hyperforin content in the preparation.

What this means in practice: the herb speeds up the liver’s metabolism of a long list of drugs, reducing their blood levels. In 2000, a pharmacokinetic interaction between St. John’s wort and cyclosporine caused acute rejection in two heart transplant patients. Subsequent research has shown that St. John’s wort altered the pharmacokinetics of drugs such as digoxin, tacrolimus, indinavir, warfarin, alprazolam, simvastatin, and oral contraceptives.

Serotonin syndrome. Combining Hypericum preparations with SSRIs or other serotonergic drugs can dangerously elevate serotonin levels, potentially producing serotonin syndrome — a serious and potentially life-threatening condition. This interaction is distinct from the CYP mechanism and is additive: two things that both raise serotonin taken together.

The full contraindication list is long. Immunosuppressants, antiretrovirals, anticoagulants, oral contraceptives, and certain chemotherapy agents are the headline categories. Anyone on prescription medications should treat Hypericum as a pharmacologically active drug before using it internally — because that is what it is.

Correspondences in modern practice

The modern magical correspondence assignment for St. John’s wort is among the most coherent in the system: the evidence for sun-fire-protection is old, consistent, and does not require twentieth-century revision to justify.

The solar correspondence flows directly from the midsummer flowering, the solar-corona appearance of the flowers, the yellow colour, and the Corona regia name recorded in medieval herbals. The fire correspondence is grounded in the documented custom of casting the herb into solstice bonfires. The protective and apotropaic assignment is the oldest and most cross-culturally consistent association the plant carries — predating the modern revival by several centuries.

Where the modern system departs from the documented record is in extending those assignments into elaborate planetary rulerships and elemental hierarchies. In Cunningham’s encyclopedia and its descendants, St. John’s wort sits under the Sun and the element of Fire — which matches the historical grain of the evidence. The more specific power-lists (love divination, prophetic dreams, exorcism) have thinner sourcing, though the divination customs around the herb on Midsummer morning — plucking sprigs to predict love’s outcome — are documented in British and Irish folk practice.

For a practitioner: if you are working a Midsummer rite, St. John’s wort is one of the most historically defensible single herbs to include. The Midsummer gathering, the bonfire offering, the protective hanging above the door — these are documented across multiple centuries and multiple countries, from named sources. The wound-oil (flowers steeped red in olive oil) is equally attested and has modern pharmacological evidence behind the anti-inflammatory and vulnerary claims. What the herb does not have a long pre-modern record for is the dream-work and astral travel associations that show up in some modern lists; those appear to be late-twentieth-century accretions to an already well-furnished plant.

Cross-references on this site: (forthcoming — Litha/Midsummer sabbat page, the Hortus Sanitatis in context, apotropaic herbs of the solstice.)