Agrao, berro, brunnenkressenkraut, crescione di fonte, Indian cress, mizugarushi, nasilord, nasturtii herba, Nasturtium officinale, oranda-garashi, scurvy grass, seladaair
The useful parts of watercress are obtained from the above ground parts of Nasturtium officinale. It contains mustard oil, vitamin C, beta carotene, minerals, and vitamins B1 B2, E, and K. Watercress has diuretic and slight antibiotic activity, which may also result from mustard oil.
Reported uses
Watercress is used for treating catarrh (an inflammation of the air passages usually involving the nose, throat, or lungs), chronic bronchitis, and mucous membrane inflammation of the respiratory tract. It’s also used as a poultice for skin irritation, a detoxifying agent, a diuretic, a spring tonic, and an appetite stimulant. Watercress is also widely cultivated as a salad herb.
Administration
- The average daily dose is 4 to 6 g of dried herb, 20 to 30 g fresh herb, or 60 to 150 g freshly pressed juice
- The average daily dose of watercress tea is 2 to 3 cups, taken by mouth. The tea is prepared by pouring 150 ml boiling water over 2 g of drug (about 1 to 2 teaspoons), covering for 10 to 15 minutes, and then straining.
Hazards
Watercress may cause GI irritation, kidney damage, and skin irritation. It may potentiate the effects of drugs such as chlorzoxazone and orphenadrine citrate. There may be additive effects if watercress is used with diuretics. Watercress may antagonize the anticoagulant effects of warfarin because of its high vitamin K content. Pregnant or breast-feeding women should avoid watercress, as should chil dren younger than age 4 years and patients with gastric ulcers, intestinal ulcers, or inflammatory kidney disease.
Clinical considerations
- Consuming large amounts of watercress may cause GI irritation.
- Watercress can be used topically as a poultice or compress, but watch for skin irritation.
- Caution patient about possible GI irritation from the effects of mustard oil on mucous membranes.
- Use caution if patient also takes an anticoagulant. Warn the patient that watercress has a vitamin K content and instruct him to watch for signs of bleeding, such as easy bruising and bleeding gums.
- Warn patient not to take watercress before seeking medical attention because doing so may delay diagnosis of a potentially serious medical condition.
- Warn patient to keep all herbal products away from children and pets.
- Tell patient to remind pharmacist of any herbal and dietary supplements that are being taken when obtaining a new prescription.
- Advise patient to consult his health care provider before using an herbal preparation because a conventional treatment with proven efficacy may be available.
Research summary
The concepts behind the use of watercress and the claims made regarding its effects have not yet been validated scientifically.