# St. John’s wort (Hypericum perforatum)

**Hiperico*; *perforata**

**Known today as.** *Hypericum perforatum*.

Kind: Plant  
Qualities: Hot and dry (Galenic tradition).  
Toxic: yes

> **Caution.** 

## 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).

## 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.

## Pharmacognosy and toxicology

- **hypericin**: 
- **hyperforin**: the 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.

**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.

## 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.

## 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

- Grieve, M. *A Modern Herbal*, “St. John’s Wort.” As published on botanical.com.
- Linde, K., et al. (2008). “St John’s wort for major depression.” *Cochrane Database of Systematic Reviews*.

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*St. John’s wort.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-09-25. The Thinking Press. https://thethinkingpress.org/materia-medica/st-johns-wort

Historical description, not medical advice.