FWD 2 Expanded Commission E: Watercress

Herbal Medicine: Expanded Commission E


Latin Name: Nasturtium officinale
Pharmacopeial Name: Nasturtii herba
Other Names: green watercress, summer watercress


Watercress is a hardy perennial herb native to Europe and temperate Asia (Uphof, 1968), cultivated and naturalized in North and South America, and the West Indies (HPUS, 1992). It is found growing wild in wetlands, particularly in calcareous regions (Grieve, 1979; HPUS, 1992). Its commercial cultivation began during the nineteenth century (Bown, 1995). The material of commerce is obtained mainly from eastern and southeastern European countries (Wichtl and Bisset, 1994). Its genus name, Nasturtium, is derived from the Latin nasus tortus, meaning convulsed or twisted nose, due to the pungent taste of its leaf (Bown, 1995; Grieve, 1979). Ancient Greek physician Hippocrates (ca. 460377 B.C.E.) used watercress for its expectorant action (Brill and Dean, 1994). According to Grieve, it has also been used as an antiscorbutic (scurvy remedy) since ancient times (Grieve, 1979). Seventeenth century English herbalist Nicholas Culpepper reported that the bruised leaves or juice, prepared as a lotion, was used topically to treat blotches, spots, and blemishes on the skin (Grieve, 1979).

Watercress contains significant amounts of micronutrients, such as manganese, iodine, iron, and calcium (Bremness, 1994; Brill and Dean, 1994), but its main active constituents, and source of pungency, may be its glucosinolates. Glucosinolates are irritating to mucous membranes and eyes and skin, and handling plants that contain them can cause allergic dermatitis (Diamond et al., 1990). In medicinal watercress preparations, these glycosides are most likely the chemicals responsible for the plant's purported effectiveness in reducing inflammation and mucous in the upper respiratory tract. However, clinical reports that confirm these actions are lacking (Hecht et al., 1995; Hecht, 1996). Some of its beneficial effects may be due to a general stimulation of metabolism and the nervous system, including autonomous regulation (Weiss, 1988).

In Germany, watercress herb, fresh or dried, is approved in the Commission E monographs for catarrh of the respiratory tract. Watercress juice is also used as a component of several cholagogue medicines such as Cholongal Saft (Wichtl and Bisset, 1994). It is listed in the supplemental volume to the German Pharmacopeia, sixth edition (Erg.B.6, 1953). In German pediatric medicine, watercress is used as a disinfectant drug for antibacterial action in the treatment of lower urinary tract infections (Schilcher, 1997). The fresh aerial parts, collected during the flowering period, are also official in the German Homeopathic Pharmacopoeia for use in the preparation of mother tinctures and liquid dilutions thereof (GHP, 1993). In the United States, watercress herb is classified in the Homeopathic Pharmacopoeia of the United States as an OTC Class D drug prepared as an alcoholic tincture of the whole flowering plant, in 45% v/v alcohol (HPUS, 1992).


Watercress consists of the fresh or dried aboveground parts of Nasturtium officinale R. Brown [Fam. Brassicaceae] and their preparations in effective dosage. The herb contains mustard glycosides and mustard oil.

Chemistry and Pharmacology

Watercress contains glucosinolates (mustard-oil glycosides) such as gluconasturtiin, a precursor of phenylethyl isothiocyanate which occurs upon hydrolysis (Chung et al., 1992), and nitriles such as 3-phenylpropionitrile, 8-methylthiooctanone nitrile (Wichtl and Bisset, 1994); minerals, including manganese, iron, phosphorus, iodine, copper, and calcium; vitamins A, C, E, and nicotinamide (Karnick, 1994; Taber, 1962).

The Commission E did not report pharmacological actions for watercress.

Watercress herb has been reported to have antibacterial (Schilcher, 1997), antiscorbutic (Nadkarni, 1976; Uphof, 1968), cholagogue (Wichtl and Bisset, 1994), and expectorant properties (Karnick, 1994).

The most recent research on watercress indicates that it may protect smokers' lungs from carcinogens present in tobacco and tobacco smoke. Diets that include watercress may help to inhibit the formation of 4- (methylnitrosamino)-1-(3-pyridyl-1-butanone), or NNK. NNK is a carcinogen present in tobacco that most likely contributes to the etiology of lung cancer, as well as of mouth and throat cancers. The constituents in watercress that cause this inhibition have not been identified, though the glucosinolate phenethyl isothiocyanate (PEITC), which is released upon chewing the leaf, is known to be a chemopreventive agent against lung cancer (Hecht et al., 1995; Hecht, 1996). Earlier animal studies demonstrated that PEITC inhibited lung tumorigenesis induced by a potent tobacco-specific carcinogenic nitrosamine. In order to determine the bioavailability of PEITC from its glucosinolate precursor, urine analysis was conducted, which has shown that PEITC is released upon ingestion of watercress leaf. This suggests that its conjugate N-acetylcysteine may be a useful biomarker compound for quantifying human exposure to PEITC in future epidemiological studies (Chung et al., 1992). Other pharmacokinetic studies have investigated the effect of watercress on the metabolism of chlorzoxazone, an in vivo clinical probe for CYP2E1 (Leclercq et al., 1998) and also its effects on acetaminophen metabolism in human volunteers (Chen et al., 1996).


The Commission E approved watercress for catarrh of the respiratory tract.

In Germany, it is also used to treat urinary tract infections in children (Schilcher, 1997). The powdered leaf is used in India as an expectorant to treat bronchitis and also to treat human liver fluke (Clonorchis sinensis) (Karnick, 1994). The fresh herb is used in naturopathy as a blood purifier (Uphof, 1968; Wichtl and Bisset, 1994) and so-called 'spring cure,' taken in combination with fresh dandelion and nettle herbs (Wichtl and Bisset, 1994), and is particularly useful for patients with chronic metabolic diseases and/or asthenia (Weiss, 1988).


Gastric and intestinal ulcers, inflammatory kidney diseases. No application for children under the age of four.

Side Effects

In rare cases, gastrointestinal complaints.

Use During Pregnancy and Lactation

Not recommended during pregnancy (McGuffin et al., 1997). No restrictions known during lactation.

Interactions with Other Drugs

None known.

Dosage and Administration

Unless otherwise prescribed: Cut herb, freshly pressed juice, and other equivalent galenical preparations.


Dried herb: 4-6 g per day (Commission E).

Fresh herb: 20-30 g per day (Commission E).

Succus: 60-150 ml freshly pressed juice per day (Commission E).

Infusion: Steep 2 g in 150 ml boiled water for 10 minutes (Wichtl and Bisset, 1994), two to three times daily before meals.


Bown, D. 1995. The Herb Society of AmericaEncyclopedia of Herbs & Their Uses. New York: DK Publishing Inc. 164, 316.

Bremness, L. 1994. Herbs. New York: DK Publishing, Inc.

Brill, S. and E. Dean. 1994. Identifying and Harvesting Edible and Medicinal Plants in Wild (and Not So Wild) Places. New York: Hearst Books. 255256.

Chen, L., S.N. Mohr, C.S. Yang. 1996. Decrease of plasma and urinary oxidative metabolites of acetaminophen after consumption of watercress by human volunteers. Clin Pharmacol Ther 60(6):651660.

Chung, F.L., M.A. Morse, K.I. Eklind, J. Lewis. 1992. Quantitation of human uptake of the anticarcinogen phenethyl isothiocyanate after a watercress meal. Cancer Epidemiol Biomarkers Prev 1(5):383388.

Diamond, S.P., S.G.Wiener, J.G. Marks, Jr. 1990. Allergic contact dermatitis to nasturtium. Dermatol Clin 8(1):7780.

Ergnzungsbuch zum Deutschen Arzneibuch, 6th ed. (Erg.B.6). 1953. Stuttgart: Deutscher Apotheker Verlag.

German Homeopathic Pharmacopoeia (GHP), 1993. Translation of the German Homopathisches Arzneibuch (HAB 1), 5th suppl. 1991 to the 1st ed. 1978. Stuttgart. Deutscher Apotheker Verlag. 291292.

Grieve, M. 1979. A Modern Herbal. New York: Dover Publications, Inc.

Hecht, S.S. 1996. Chemoprevention of lung cancer by isothiocyanates. Adv Exp Med Biol 40(1):111.

Hecht, S.S., F.L. Chung, J.P. Richie, Jr. et al. 1995. Effects of watercress consumption on metabolism of a tobacco-specific lung carcinogen in smokers. Cancer Epidemiol Biomarkers Prev 4(8):877884.

The Homeopathic Pharmacopoeia of the United States (HPUS). 1992. Arlington, VA: Pharmacopoeia Convention of the American Institute of Homeopathy.

Karnick, C.R. 1994. Pharmacopoeial Standards of Herbal Plants. Delhi: Sri Satguru Publications. Vol. 2:139.

Leclercq, I., J.P. Desager, Y. Horsmans. 1998. Inhibition of chlorzoxazone metabolism, a clinical probe for CYP2E1, by a single ingestion of watercress. Clin Pharmacol Ther 64(2):144149.

McGuffin, M., C. Hobbs, R. Upton, A. Goldberg. 1997. American Herbal Product Association's Botanical Safety Handbook. Boca Raton: CRC Press. 78.

Nadkarni, K.M. 1976. Indian Materia Medica. Bombay: Popular Prakashan. 843.

Schilcher, H. 1997. Phytotherapy in Paediatrics: Handbook for Physicians and Pharmacists. Stuttgart: Medpharm Scientific Publishers. 5556.

Taber, C.W. 1962. Taber's Cyclopedic Medical Dictionary, 9th ed. Philadelphia: F.A. Davis Company. W2.

Uphof, J.C. 1968. Dictionary of Economic Plants, 2nd ed. New York: Verlag von J. Cramer. 357.

Weiss, R.F. 1988. Herbal Medicine. Beaconsfield, England: Beaconsfield Publishers. 274275.

Wichtl, M. and N.G. Bisset (eds.). 1994. Herbal Drugs and Phytopharmaceuticals. Stuttgart: Medpharm Scientific Publishers. 353354.

Additional Resources

Bruneton, J. 1995. Pharmacognosy, Phytochemistry, Medicinal Plants. Paris: Lavoisier Publishing.

Cruz, A. 1970. [Remarkable antimitotic action of watercress (Nasturtium officinale) on some experimental tumors] [In Portuguese]. Hospital (Rio De J) 77(3):943952.

Hutchens, A. 1991. Indian Herbology of North America. Boston: Shambala.

This material was adapted from The Complete German Commission E MonographsTherapeutic Guide to Herbal Medicines. M. Blumenthal, W.R. Busse, A. Goldberg, J. Gruenwald, T. Hall, C.W. Riggins, R.S. Rister (eds.) S. Klein and R.S. Rister (trans.). 1998. Austin: American Botanical Council; Boston: Integrative Medicine Communications.

1) The Overview section is new information.

2) Description, Chemistry and Pharmacology, Uses, Contraindications, Side Effects, Interactions with Other Drugs, and Dosage sections have been drawn from the original work. Additional information has been added in some or all of these sections, as noted with references.

3) The dosage for equivalent preparations (tea infusion, fluidextract, and tincture) have been provided based on the following example:

  • Unless otherwise prescribed: 2 g per day of [powdered, crushed, cut or whole] [plant part]
  • Infusion: 2 g in 150 ml of water
  • Fluidextract 1:1 (g/ml): 2 ml
  • Tincture 1:5 (g/ml): 10 ml

4) The References and Additional Resources sections are new sections. Additional Resources are not cited in the monograph but are included for research purposes.

This monograph, published by the Commission E in 1994, was modified based on new scientific research. It contains more extensive pharmacological and therapeutic information taken directly from the Commission E.

Excerpt from Herbal Medicine: Expanded Commission E Monographs
Copyright 2000 American Botanical Council
Published by Integrative Medicine Communications
Available from the American Botanical Council.