Health Care Professional Information

Scientific Name
Stillingia sylvatica
Common Name

Stillingia treculeana, queen’s root, queen’s delight, yaw root

Clinical Summary

Derived from the root of the plant, this supplement is used to treat syphilis, bronchitis, constipation, hemorrhoids, skin conditions, and is an ingredient in the Hoxsey herbal therapy, used as a cancer treatment.
Stillingia contains diterpene esters that cause mucosal irritation and skin eruptions. Other reported toxicities include vertigo, diarrhea, nausea, vomiting, muscle ache, pruritus, cough, fatigue, and sweating. No clinical data support the use of this supplement for any proposed claim.
Significant toxicity can occur following administration (1).

Purported Uses
  • Bronchitis
  • Cancer treatment
  • Chest congestion
  • Constipation
  • Hemorrhoids
  • Laryngitis
  • Skin abscesses
  • Spasms
  • Syphilis
  • Terpenoids: Stillingia factors S1-S8
  • Diterpene esters: Phorbol, ingenane, daphnane
  • Volatile oils
  • Other: Sylvacrol, resinic acid, stillingine, tannin, hydrocyanic acid (leaf and stem)
Mechanism of Action

Stillingia has not been evaluated for any proposed claim. It contains diterpene esters, toxic irritants that can cause swelling and inflammation of the skin (1). In vitro research suggests that diterpene esters may have antitumor activity (2), but this has not been confirmed with stillingia root.


The diterpene esters in stillingia are irritants to the skin and mucous membranes (1).

Adverse Reactions

Toxicity: Vertigo, burning sensation on mucous membranes, diarrhea, nausea, vomiting, muscle ache, pruritus, skin eruptions, cough, fatigue, sweating (1).

Herb-Drug Interactions

None known.

  1. Newall C, et al. Herbal Medicines: A Guide for Health-Care Professionals, 1st ed. London: Pharmaceutical Press; 1996.
  2. Szallasi Z, et al. Nonpromoting 12-deoxyphorbol 13-esters inhibit phorbol 12-myristate 13-acetate induced tumor promotion in CD-1 mouse skin. Cancer Res 1993;53:2507-12.

Consumer Information

How It Works

Bottom Line: There is no evidence to support use of Stillingia to treat cancer, infections, or other medical conditions.

Stillingia is a root extract. It is known to contain chemicals called diterpene esters, toxic irritants that can cause swelling and inflammation of the skin. One laboratory experiment suggested that diterpene esters can halt the growth of cancer cells, but this has not been confirmed with stillingia root.

Purported Uses

There is no scientific evidence to support any of the uses below:

  • To treat bronchitis and relieve chest congestion
  • To treat cancer as part of the Hoxsey Herbal Therapy
  • To relieve constipation'
  • To treat hemorrhoids
  • To treat laryngitis
  • To treat skin abscesses
  • To treat muscle spasms
  • To treat syphilis
Patient Warnings
  • Stillingia contains chemicals called diterpene esters, which are known to irritate skin and mucous membranes. Major toxicities can occur when this herb is taken by mouth.
Side Effects
  • Vertigo
  • Burning sensation on mucous membranes
  • Diarrhea
  • Nausea
  • Vomiting
  • Muscle aches
  • Pruritus (itching of the skin)
  • Skin eruptions
  • Cough
  • Fatigue
  • Sweating
Special Point
  • Stillingia root is one of the ingredients in the Hoxsey Herbal Therapy, which is promoted for treating cancer but has never been proven to be effective.
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