# Wild yam (Dioscorea villosa) *Colic root, rheumatism root, dioscorea; German *Wilde Yamwurzel*; *Dioscorea villosa* L.* **Known today as.** *Dioscorea villosa*, of the family Dioscoreaceae, a slender perennial vine of the United States and Canada, twining over fences and bushes, with heart-shaped leaves downy beneath and tiny greenish-yellow flowers. The drug is the hard, woody rhizome, which King’s Dispensatory calls one of the hardest of rhizomes, very difficult to powder or crush, with no odour and little taste beyond a slight acridity. Grieve and King’s both report that it loses its virtue after the first year, so that it should be gathered fresh each year. Grieve records much saponin in the root; King’s that the so-called dioscorein is not a definite principle but simply a dried extract. Kind: Plant > **Caution.** Neither Grieve nor King’s reports poisoning by this species. King’s notes that the tincture in large doses produces vomiting, and Grieve records that an alkaloid from a Javanese species, *D. hirsuta*, is a convulsive poison resembling picrotoxin but much feebler. Its safety as a medicine has not been established by the sources read for this entry. ## What was it used for? A remedy for colic. King’s Dispensatory calls it “a favorite therapeutical agent among Eclectic physicians,” used for more than sixty years, and above all “a specific in bilious colic”; it was also given in other colics and painful bowel complaints, in painful cholera morbus with cramps, spasmodic hiccough, painful menstruation, after-pains, and, with the bark of *Cornus sericea*, in the nausea and vomiting of pregnancy. Grieve repeats it as “perhaps the best relief and promptest cure for bilious colic.” ## What does modern science say? No European monograph covers it, and the searches of Europe PMC made for this entry found no controlled clinical trial of the root itself. An expert panel on cosmetic ingredients, reviewing the matter again in 2023, reaffirmed its 2004 conclusion that wild yam root extract is safe as a cosmetic ingredient in the practices of use and concentrations it describes. ## Pharmacognosy and toxicology - **saponin**: much of it in the root, by Grieve’s account - **acrid resin**: in which, King’s says, its virtues appear to reside **Mechanism.** Not established in the sources read for this entry. **Standing.** There is no European monograph, and no controlled clinical trial of the root was found for this entry. Its extract is judged safe as a cosmetic ingredient (2023). ## What lore surrounds it? Grieve notes that there are upwards of 150 kinds of *Dioscorea*, many edible like the potato, and that an Indo-Chinese species is used as a dye in southern China. ## What did the older authorities say? **Felter and Lloyd, *King’s American Dispensatory* (1898).** John King admitted that he had called it an antispasmodic “solely for the reason that it cures bilious colic,” and that nearly all remedies had been classified so, “not from any positive knowledge of their action, but from the results following their administration.” The book also tells how, from about 1850, root-diggers mixed a second, knotty rhizome, from a smooth-leaved variety, into the trade; purchasers at first refused it, but as the true root grew scarce they had to accept it, and by the 1890s little of the original drug was to be found, though Eclectic physicians refused the “false” root as without its virtues. ## Sources - Grieve, M. *A Modern Herbal*, “Yam, Wild.” As published on botanical.com. - Felter, H. W., & Lloyd, J. U. (1898). *King’s American Dispensatory*, vol. 1, “Dioscorea.” Internet Archive, kingsamericandis01kinguoft. - Raj PS, et al. (2023). Dioscorea Villosa (Wild Yam) Root Extract. *International journal of toxicology*. PMID 37751575. - Grieve, M. *A Modern Herbal*, “Yam, Wild.” As published on botanical.com. - Felter, H. W., & Lloyd, J. U. (1898). *King’s American Dispensatory*, vol. 1, “Dioscorea.” Internet Archive, kingsamericandis01kinguoft. - Raj PS, et al. (2023). Dioscorea Villosa (Wild Yam) Root Extract. *International journal of toxicology*. PMID 37751575. --- *Wild yam.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-17. The Thinking Press. https://thethinkingpress.org/materia-medica/wild-yam Historical description, not medical advice.