Pleurisy root
Butterfly weed, orange milkweed, orange swallow-wort, swallow-wort, silkweed, tuber root, wind root, colic root, white root, flux root, Canada root; Asclepias tuberosa L.
- Known today as
- Asclepias tuberosa, a handsome perennial of North America from Canada southward, most abundant in the south, one to one and a half feet high, with clusters of bright, deep orange flowers in summer; Grieve placed it in the family Asclepiadaceae. Unlike the other milkweeds it has little or none of their milky juice. The large spindle-shaped root is the drug: orange-brown outside, whitish within, with a bitterish, somewhat acrid taste. King’s traces the genus name to Aesculapius.
- Kind
- Plant, in 1 older authority
- Constituents
- asclepiadin, cardiac glycosides
- Earliest authority here
- Felter and Lloyd, King’s American Dispensatory (1898)
- In other databases
- Plants of the World Online · GBIF · Wikidata
Caution. Grieve notes that in large doses it acts as an emetic and purgative. A 2026 case report describes a gardener, a contact-lens wearer, who suffered sudden corneal clouding and near loss of vision hours after handling the plant; the authors attribute it to its cardiac glycosides, and she improved quickly with treatment. None of the sources read for this entry reports on its safety as a medicine.
Pleurisy root: what was it used for?
A remedy for the chest and a sweat-inducer. Grieve calls it antispasmodic, diaphoretic, expectorant, tonic, carminative, and mildly cathartic, of great use in pleurisy, “mitigating the pain and relieving the difficulty of breathing,” and in other chest complaints, diarrhoea, dysentery, and rheumatism. King’s counts it, with crawley, among the chief diaphoretics of the Eclectic materia medica, and notes that it “has a deservedly good reputation in respiratory diseases.”
Pleurisy root: what does modern science say?
No European monograph for it was found for this entry. It was official in the United States Pharmacopoeia until shortly before Grieve wrote, and the searches of Europe PMC made for this entry found no clinical trial of it.
Pleurisy root: is it poisonous?
Yes, in some form or dose. Grieve notes that in large doses it acts as an emetic and purgative. A 2026 case report describes a gardener, a contact-lens wearer, who suffered sudden corneal clouding and near loss of vision hours after handling the plant; the authors attribute it to its cardiac glycosides, and she improved quickly with treatment. None of the sources read for this entry reports on its safety as a medicine. Historical description, not medical advice; in a poisoning, call a poison centre.
Pharmacognosy & Toxicology
- Constituents
- asclepiadina glucosidal principle, by Grieve’s account
- cardiac glycosidesto which a 2026 case report attributes eye injury from handling the plant
- Mechanism
- Not established in the sources read for this entry.
- Standing
- There is no European monograph. It was official in the United States Pharmacopoeia until shortly before Grieve wrote.
- Grieve, M. A Modern Herbal, “Pleurisy Root.” As published on botanical.com. Read in full · the text read
- Lu A, et al. (2026). Toxic Keratoconjunctivitis from Milkweed (Asclepias tuberosa) Exposure in a Contact Lens Wearer. The Journal of emergency medicine. PMID 41903404. Abstract read · the text read
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.
Pleurisy root: what lore surrounds it?
Grieve records that “the Western Indians boil the tubers for food, prepare a crude sugar from the flowers and eat the young seed-pods, after boiling them, with buffalo meat,” and that some Canadian tribes ate the young shoots like asparagus.
Pleurisy root: what did the older authorities say?
- Felter and Lloyd, King’s American Dispensatory (1898)
- “Asclepias, or pleurisy root, was one of the most common of the indigenous medicines employed by the Eclectic fathers,” the book records, and its name indicated “one of its most important applications.” In 1898 the authors thought it had “fallen into unmerited neglect.” Of the plant in flower they wrote that “for miles along the railways clusters of the rich, deep orange flowers of the butterfly weed, as it is called, bedeck the fields.”
Sources
- Grieve, M. A Modern Herbal, “Pleurisy Root.” As published on botanical.com. Read in full · the text read
- Felter, H. W., & Lloyd, J. U. (1898). King’s American Dispensatory, vol. 1, “Asclepias.” Internet Archive, kingsamericandis01kinguoft. Read in part · the text read
- Lu A, et al. (2026). Toxic Keratoconjunctivitis from Milkweed (Asclepias tuberosa) Exposure in a Contact Lens Wearer. The Journal of emergency medicine. PMID 41903404. Abstract read · the text read
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
- 3 cited: 1 read in full, 1 read in part, 1 abstract read. 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.
Club members can point at a technical term in this entry, such as a constituent, an action, or a word of Jung’s, to read its definition from the source. The Club.
Cite This Entry
Version 1 · first published October 17, 2026
- Chicago
“Pleurisy root.” In Materia Medica, edited by B. C. P. Statema. Version 1. The Thinking Press, 2026–. Last modified October 17, 2026. https://thethinkingpress.org/materia-medica/pleurisy-root.
- MLA
“Pleurisy root.” Materia Medica, edited by B. C. P. Statema, version 1, The Thinking Press, 17 Oct. 2026, thethinkingpress.org/materia-medica/pleurisy-root. Accessed 17 Oct. 2026.
- APA
Pleurisy root. (2026, October 17). In B. C. P. Statema (Ed.), Materia medica (Version 1). The Thinking Press. Retrieved October 17, 2026, from https://thethinkingpress.org/materia-medica/pleurisy-root
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See Also
Sharing cardiac glycosides
Drawing on the same sources: Grieve, Felter
Pokeweed · Plantain · Pomegranate · Peony · Pumpkin seed · the bibliography →
Nearby in the alphabet
Poison fire coral (finger-like fungus of Korea, Japan, China, and Indonesia) · Pink rock-rose · Polypody of mercurialis, syrup of · Pilgrim badges and ampullae · Pomander (of ambergris, musk, civet, and spices, carried in a pierced case) · Pilewort
Historical description, not medical advice.
