Heart Disease 8. The plants have their primary origins in East Africa and Madagascar but are cultivated throughout the world. The primary species originally used in cough preparations in Germany, D. rotundifolia, D. intermedia and D. anglica, are rarely used currently due to threat of extinction. Instead, D. ramentacea and other Drosera species from Australia are employed. These naphthaquinones include plumbagin, ramentone, ramentaceon, and biramentaceone.
Pharmacological studies show a clear antispasmodic effect in the respiratory tract.
This finding has not been repeated in humans. Human studies 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. The average daily amount of sundew for adults and children older than twelve years of age is 3 grams. One cup may be drunk three to four times daily. In Europe, liquid preparations of sundew are often combined with thyme , another anti-tussive, in cough syrups for adults and children.