St. John’s wort

Statema, B. C. P.

Plant

St. John’s wort

Hiperico; perforata

Known today as: Hypericum perforatum.
Kind: Plant, in 2 older authorities
Constituents: hypericin, hyperforin
Earliest authority here: Dioscorides (c. AD 40–90)
Qualities: Hot and dry (Galenic tradition). What the degrees mean
In other databases: Plants of the World Online search · GBIF search · Wikidata search
In the Canale glossary: On the Manner of Discerning and Healing the Bewitched, Appendix A: Part Three, Chapter 6: Remedies Given by Mouth After the Purge

Caution. Hazardous in some form or dose; see the modern assessment below.

St. John’s wort: what did Canale use it for?

Canale’s chief plant: seed, juice, flowers, and oil in the powders, electuary, conserve, bath, fumigations, and oils; worn on the person against every hex, “and from its effect called Fuga Daemonum” (chs. 6–10; notes XLVI–XLVII).

St. John’s wort: how is it taken as a tea?

An infusion given before bed for children who wet the bed, and for chronic catarrh of the lungs, bowels, or urinary passages.

All the herbal teas of the database. Historical directions, not medical advice.

St. John’s wort: what does modern science say?

The most striking case in the glossary of a traditional use borne out. Controlled trials show St. John’s wort works about as well as standard antidepressants for mild to moderate depression, the condition a modern reader might recognize in many of Canale’s “melancholic” bewitched. It also weakens many prescription medicines by speeding their breakdown.

St. John’s wort: is it poisonous?

Yes, in some form or dose. Historical description, not medical advice; in a poisoning, call a poison centre.

Pharmacognosy & Toxicology

Constituents

hypericin ChEMBL
hyperforin ChEMBLthe chief antidepressant constituent

Mechanism

Hyperforin inhibits the reuptake of serotonin, noradrenaline, and dopamine, and induces the liver’s CYP3A4, so that many drugs are cleared too fast: the contraceptive pill, ciclosporin, warfarin, antiretrovirals.

Checked against ChEMBL

hyperforin: No measurement in ChEMBL for “inhibits the reuptake of serotonin, noradrenaline, and dopamine” (2 activities recorded, none against the target named); the line rests on its references.
hyperforin: No measurement in ChEMBL for “induces the liver's CYP3A4” (2 activities recorded, none against the target named); the line rests on its references.

Toxic dose

Photosensitivity in fair skins; the interactions are the danger.

Standing

Licensed in Germany for mild to moderate depression; a Cochrane review finds it as effective as standard antidepressants for mild cases.

Linde, K., et al. (2008). “St John’s wort for major depression.” Cochrane Database of Systematic Reviews. Verified against its record · doi:10.1002/14651858.cd000448.pub3

Constituent names open the compound’s record at PubChem, and “ChEMBL” beside a name opens its record at ChEMBL, the European Bioinformatics Institute’s database of bioactive molecules. Where a mechanism line was checked against ChEMBL (ChEMBL 37, read 1 October 2026), the check is shown with the measured value and its source paper, or says plainly that nothing has been measured. Doses are as the references give them, for description only; this is not medical advice. Each source carries the result of its check against Crossref, PubMed, or the authority’s page: see Verification.

What Medicine Makes of It

The Nightmare and the HagThe incubus that sits on the chest, and sleep paralysis.
Melancholy and the DemonThe black bile, the devil’s bath, and depression.
The IncubusThe demon lover of the night, and the sleep that cannot move.

St. John’s wort: what lore surrounds it?

Gathered on St. John’s Eve (23 June), when its yellow flowers are at their height, and hung over doors and windows; the red juice of the crushed flowers was read as the blood of the Baptist. The name fuga daemonum, “flight of demons,” was common to the exorcists’ manuals of Canale’s century.

St. John’s wort: what did the older authorities say?

Dioscorides: Describes hyperikon as a diuretic and emmenagogue, taken in wine against tertian and quartan fevers and for sciatica, and laid on burns.
Paracelsus: Praised it above other herbs as a wound-healer; its red oil, the flowers steeped in olive oil in the sun, became a fixture of the apothecary.

Sources

[91] National Center for Complementary and Integrative Health, NIH. Usefulness and Safety pages: Boswellia (April 2025); Chamomile (November 2024); St. John’s Wort (May 2025). nccih.nih.gov. Book, not indexed
[97] Peterson, B., & Nguyen, H. (2023). St. John’s Wort. StatPearls. Treasure Island (FL): StatPearls Publishing; updated 16 May 2023. Book, seen in reviews

Grieve, M. A Modern Herbal, “St. John’s Wort.” As published on botanical.com.

Verification

Checked

October 1, 2026

Passes

Every sentence read against its sources, in the pass over the remaining 343 entries
The Standing line checked against the authority it names (EMA, WHO, FDA, CITES, Commission E)
Every dated or regulatory claim checked by category across the database
The mechanism read against ChEMBL (ChEMBL 37): curated mechanisms and measured activity

Sources

4 cited: 1 verified against its record, 1 book, seen in reviews, 1 book, not indexed, 1 not yet checked.

Corrections

None were needed.

What was checked, how, and what was found is set out on the Verification page. A checked source is one whose record was found; it does not make the entry medical advice.

Cite This Entry

Version 1 · first published September 25, 2026

Chicago: “St. John’s wort.” In Materia Medica, edited by B. C. P. Statema. Version 1. The Thinking Press, 2026–. Last modified September 25, 2026. https://thethinkingpress.org/materia-medica/st-johns-wort.
MLA: “St. John’s wort.” Materia Medica, edited by B. C. P. Statema, version 1, The Thinking Press, 25 Sept. 2026, thethinkingpress.org/materia-medica/st-johns-wort. Accessed 8 Oct. 2026.
APA: St. John’s wort. (2026, September 25). In B. C. P. Statema (Ed.), Materia medica (Version 1). The Thinking Press. Retrieved October 8, 2026, from https://thethinkingpress.org/materia-medica/st-johns-wort

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