Walnut, middle bark of

Statema, B. C. P.

Plant

Walnut, middle bark of

Scorza mezzana della noce

Known today as: The inner bark of Juglans regia.
Kind: Plant, in 2 older authorities
Constituents: juglone, tannins, ellagic acid
Earliest authority here: Dioscorides (c. AD 40–90)
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 5: Vomitory Medicines

Revised October 1, 2026: Tradition, lore, modern assessment, and sources extended. Version 1, first published September 25, 2026.

Walnut, middle bark of: what did Canale use it for?

Powdered, a dram at a time, as a vomit (ch. 5).

Walnut, middle bark of: what does modern science say?

Walnut bark is purgative, with a bitter, astringent taste. Juglone, the quinone that stains the hands and kills the plants beneath the tree, is a strong irritant and purgative; a dram of the bark powder would act as Canale says, and would not be given now.

Pharmacognosy & Toxicology

Constituents

juglone ChEMBL5-hydroxy-1,4-naphthoquinone, in the green husk, leaf, and inner bark
tannins
ellagic acid ChEMBL

Mechanism

Juglone is a reactive quinone that irritates the gut, which is Canale’s vomit at a dram of the bark, and is antifungal and allelopathic, poisoning the plants under a walnut tree. The leaf’s tannins are the astringent of the leaf tea.

Toxic dose

The bark at Canale’s dram nauseates; the leaf tea is safe; juglone stains the skin and sensitises.

Standing

Walnut leaf has an EMA monograph (2014) for minor skin inflammation and sweating of the hands and feet; the bark has none.

EMA/HMPC (2014). Community herbal monograph on Juglans regia L., folium (EMA/HMPC/346737/2011). Verified against its record
Strugstad, M. P., and Despotovski, S. (2012). “A summary of extraction, synthesis, properties, and potential uses of juglone.” Journal of Ecosystems and Management 13. Verified against its record · doi:10.22230/jem.2012v13n3a119

The abstract of each source, beneath its citation. For Club members. About the Club or sign in.

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.

Walnut, middle bark of: what lore surrounds it?

The walnut tree, Juglans, is Jove’s nut; the witches of Benevento were said to gather under a great walnut, and the tree’s poisonous shade is an old Italian belief that modern botany explains by the juglone its roots exude.

Walnut, middle bark of: what did the older authorities say?

Dioscorides: Gives the green rind and the leaves of the walnut as astringent, and the Latin herbals the inner bark, boiled, as a purge and a vomit, “the middle bark” being that between the outer rind and the wood.
Pliny: Says the walnut was brought from Persia by the kings, and that its shade and its smell are heavy and hurt the head, whence its ill name among the old.

Sources

[54] Grieve, M. (1931). A Modern Herbal. Online edition, botanical.com, cited under the plant concerned. Read in part · the text read

Pliny, Natural History XV–XVII. Primary text
Dioscorides, De materia medica I. Primary text

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

Sources

5 cited: 1 read in part, 2 verified against its record, 2 primary text. 1 with the abstract on file.

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 · last revised October 1, 2026

Chicago: “Walnut, middle bark of.” In Materia Medica, edited by B. C. P. Statema. Version 1. The Thinking Press, 2026–. Last modified October 1, 2026. https://thethinkingpress.org/materia-medica/walnut-middle-bark-of.
MLA: “Walnut, middle bark of.” Materia Medica, edited by B. C. P. Statema, version 1, The Thinking Press, 1 Oct. 2026, thethinkingpress.org/materia-medica/walnut-middle-bark-of. Accessed 8 Oct. 2026.
APA: Walnut, middle bark of. (2026, October 1). In B. C. P. Statema (Ed.), Materia medica (Version 1). The Thinking Press. Retrieved October 8, 2026, from https://thethinkingpress.org/materia-medica/walnut-middle-bark-of

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