Sundew

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

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

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

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.

At the recommended amounts, 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.