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Botanical Description & Habitat

Drosera rotundifolia


Common Names
Dew plant                 Lustwort
Round-leaved sundew        Youthwort

Found in wet and moist places, sphagnum bogs and marshes, in North America, Europe and Asia.

Medicinal Parts
The herb, collected May to September

Historical Properties & Uses

Sundew has been used in folklore around the world for respiratory problems requiring an antispasmodic and expectorant, including bronchitis, asthma, coughs and whooping cough. Sundew is used additionally as a carminative for upset stomach, nausea, flatulence and heartburn.

One unique feature of sundew is the recommendation less is better. In too large of dosages, it loses its action completely. Sundew is an important source of a substance that is an effective antimicrobial agent.

Some European countries have used sundew as an aphrodisiac. It has occasionally been used in the treatment of arteriosclerosis, but apparently not many cultures discovered how to do this.

Science has found the antispasmodic and expectorant principles in sundew, and has suggested a mechanism whereby an arthritic property could be expected. Externally, sundew juice is applied to warts. This action may be related to the alkaloid content.

Drosera is a popular homeopathic treatment for rheumatic pain and pulmonary tuberculosis.

This herb has approval status by the German Commission E for coughs.


Blumenthal, M (Ed.): The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council. Austin, TX. 1998.

Method of Action

Sundew has Spasmolytic and Antitussive Action
Sundew contains a yellow crystalline substance, called carboy-oxy-naphthoquinone (CON) has been shown to have good spasmolytic, antitussive action. This is in perfect agreement with folklore usage. Sundew extract in small amounts added to thyme extract enhances the action of the latter in the treatment of whooping cough. The spasmolytic effect of sundew has been found to exert a weak influence on peripheral vessels. Used for extended periods in very small amounts, sundew could thereby exert an anti-arteriosclerotic action.

Sundew has Antimicrobial Action
The antimicrobial action of sundew has been well-established in routine screening trials, as well as in experimental trials designed specifically to isolate and identify this chemical. Success in the latter efforts was achieved in the early '50's, with isolation of the spasmolytic CON, and shortly thereafter with the isolation of 2-methyl-5-oxy-1-4-naphthaquinone possessing extremely strong antibiotic action, pneumococci, strepto- and staphylococcus microorganisms. This same chemical occurs as plumbagone in plumbago spp.

The British Herbal Pharmacopoeia recognizes sundew as an antispasmodic, demulcent, expectorant appearing to exert a relaxing effect on bronchial musculature, for use in the treatment of bronchitis, asthma, pertussis, tracheitis and gastric ulceration. It is specifically indicated for asthma and chronic bronchitis with peptic ulceration or gastritis; combined with euphorbia, gum weed and senega (Virginia snake root).

Drug Interactions & Precautions

Possible Interactions
The antacid nature of sundew may decrease or delay the absorption of nalidixic acid and the sulfonamides.

Due to the spasmolytic nature of sundew it may interact in unknown ways with CNS depressants or stimulants.

There is evidence combining bactericidal and bacteriostatic agents will lower the effectiveness of the '-static' variety. How this finding applies to herbal antibiotics is not known.

Safety Factors & Toxicity

Sundew has no side effects in therapeutic dosages.

This herb has approval status by the German Commission E.


Blumenthal, M (Ed.): The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council. Austin, TX. 1998.

Preparation & Administration

Use three times daily

Use 1-2g of dried plant

Liquid Extract
Use 0.5-2ml of 1:1 in 25% alcohol

Use 0.5-1ml of 1:5 in 60% alcohol


Blumenthal, M (Ed.): The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council. Austin, TX. 1998.

British Herbal Pharmacopoeia, British Herbal Medicine Association, 1983.

Danzel, J. J. Pharm. Belg., 4,3, 1949.

Fitzpatrick, F. Plant substances active against mycobacterium tuberculosis. Antibiotics and Chemotherapy, 4(5), 528-536, 1954.

Gordonoff, T. Schw. Med. Wschr., 81, 111, 1951.

Mowrey, Daniel B., Ph.D. Exper. Psych., Brigham Young University. Director of Nebo Institute of Herbal Sciences. Director of Behavior Change Agent Training Institute. Director of Research, Nova Corp.

Nishikawa, H. Screening tests for antibiotaic action of plant extracts. Japanese Journal of Experimental Medicine, 20, 337-349, 1949.

Weiss, R.F. Herbal Med. Beaconsfield Pub., LTD, Beaconsfield, Eng., 1988.


Drosera rotundifolia

? Southwest School of Botanical Medicine


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