Sundew

Botanical names: Drosera rotundifolia, Drosera ramentacea, Drosera intermedia, Drosera anglica

Parts used and where grown

These carnivorous plants have their primary origins in East Africa and Madagascar but are cultivated throughout the world. The main species originally used in cough preparations in Germany, D. rotundifolia, D. intermedia and D. anglica, are now rarely used currently due to threat of extinction. Instead, D. ramentacea and other Drosera species from Australia are employed. Herbal medicine preparations are made primarily from the roots, flowers, and fruit-like capsules.¹

Sundew has been used in connection with the following conditions (refer to the individual health concern for complete information):

Science Ratings	Health Concerns
	Coughs (particularly dry and irritating)
Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For a herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Historical or traditional use (may or may not be supported by scientific studies)

The historical use of sundew is similar to its use in modern herbal medicine. In 1685, Johann Schroder wrote in his book, The Apothecary or a Treasure Chest of Valuable Medicines, that sundew was a beneficial herb that “cures lung ailments and cures coughs.” Sundew tea was specifically recommended in Europe by herbalists for dry coughs, bronchitis, whooping cough, asthma, and “bronchial cramps.”²

Active constituents

Naphthaquinones are believed to give sundew the antispasmodic (or relief from coughing spasms) effect that has made it such a popular cough remedy in Europe.³ These naphthaquinones include plumbagin, ramentone, ramentaceon, and biramentaceone. Pharmacological studies show a clear antispasmodic effect in the respiratory tract.⁴ One naphthaquinone was found in an animal study to be comparable to codeine in its ability to suppress the impulse to cough. This finding has not been repeated in human studies, however. Based on this effect, sundew is often referred to as an herbal antitussive (a substance capable of preventing or relieving coughing). Human trials have shown its value either alone or in combination with other herbs for the treatment of coughs associated with bronchitis, pharyngitis, laryngitis, and even whooping cough.⁵

How much is usually taken?

Adults and children older than 12 years of age may take 1/2–3/4 teaspoons (3 grams) per day.⁶ To prepare tea, boiling water is poured over 1/4–1/2 teaspoon (1 to 2 grams) of finely cut sundew root and above-ground parts, then strained after steeping for ten minutes. One cup (250 ml) may be taken three to four times daily. In Europe, liquid preparations of sundew are often combined with thyme, another antitussive, in cough syrups for adults and children. A tincture of sundew, 1/8–1/4 teaspoon (0.5 to 1.0 ml) three times per day, is also sometimes used.

Are there any side effects or interactions?

At the amounts listed above, sundew is thought to be safe.⁷ Higher levels may lead to gastrointestinal irritation in some people. Pregnant and breast-feeding women should avoid use of sundew.

At the time of writing, there were no well-known drug interactions with sundew.

References
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1. Wichtl M. Herbal Drugs and Phytopharmacetuicals. Boca Raton, FL: CRC Press, 1994, 178–81.

2. Schilcher H, Elzer M. Drosera (Sundew): A proven antitussive. Zeitschrift Phytotherapie 1993;14:50–4.

3. Luckner R, Luckner M. Naphthaquinone derivative from Drosera ramentacea Burch. Ex harv. Et ond. Pharmazie 1970;25:261–5.

4. Krahl R. An effective principle from Drosera rotundifolia. Arzneim-Forsch Drug Res 1956;6:617–9.

5. Schilcher H, Elzer M. Drosera (Sundew): A proven antitussive. Zeitschrift Phytotherapie 1993;14:50–4.

6. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Austin: American Botanical Council and Boston: Integrative Medicine Communications, 1998, 217–8.

7. Newall CA, Anderson LA, Phillipson JD. Herbal Medicines: A Guide for Health-Care Professionals. London: The Pharmaceutical Press, 1996, 100.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or chemist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires March 2007.

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