Watercress in Essiac Tea: Uses, History & Research

Watercress is one of the eight ingredients in the Genuine Essiac™ formula. The plant, Nasturtium officinale, is a leafy, semi-aquatic member of the mustard family (Brassicaceae). Known for its peppery flavor, watercress has been eaten as a vegetable for generations and is also documented in traditional botanical preparations. 1 2

Unlike the roots and bark in Genuine Essiac, watercress is a green, leafy plant that grows in or alongside fresh, flowing water. Researchers have studied its naturally occurring glucosinolates, isothiocyanates, carotenoids, and phenolic compounds. 3

In Genuine Essiac™, watercress is included in a specific proportion as one ingredient of the complete eight-herb formula.

What Is Watercress (Nasturtium officinale)?

Watercress (Nasturtium officinale) is a perennial plant adapted to springs, streams, and other wet environments. It produces trailing stems, rounded to oval leaflets, and small white flowers. It is native to Eurasia and has become established in many other regions, including North America. 1

Although its scientific genus is Nasturtium, watercress is not the same plant as the colorful garden nasturtiums commonly grown for edible flowers, which belong to the genus Tropaeolum. Scientific names help distinguish plants that share similar everyday names.

A Leafy Green With a Long Culinary History

Watercress has a history as a fresh food, often eaten in salads, sandwiches, and soups. Its distinctive peppery flavor is characteristic of cruciferous vegetables, a group that also includes mustard greens, radishes, and cabbage. 2

Watercress is a source of bitter in the diet and the presence of this ingredient is part of why the expanded eight-herb blends of Essiac tea tend to taste a bit more bitter than older four-herb blends. However, if you don't like anything that tastes bitter, luckily there are many things you can add that will allow you to change the taste of Essiac tea.

Historical botanical literature also describes watercress in traditional practices in several regions, including parts of Europe, Asia, and North Africa. Such accounts describe how people have used the plant; they do not establish that a finished herbal tea prevents or treats disease. 2

Watercress and the Eight-Herb Essiac Formula

Essiac products are available in different formulations. Some contain four herbs, while the expanded Genuine Essiac formula contains eight ingredients.

The complete Genuine Essiac™ formula contains:

• Burdock root
• Sheep sorrel, including the root
• Slippery elm bark
• Turkish rhubarb root
• Red clover
• Watercress
• Blessed thistle
• Kelp (Ascophyllum nodosum)

Each ingredient is included in a specific proportion. Watercress is one component of the blend, not a standalone substitute for the finished eight-herb tea.

What Is Naturally Found in Watercress?

Watercress is of scientific interest because it contains a range of compounds also found in other cruciferous vegetables. Its chemical composition varies with growing conditions, plant part, maturity, and processing. 3 4

Glucosinolates

Glucosinolates are naturally occurring sulfur-containing compounds found in mustard-family plants. A notable glucosinolate in watercress is gluconasturtiin. When plant tissue is disrupted, an enzyme called myrosinase can convert gluconasturtiin into related compounds, including phenethyl isothiocyanate (PEITC). 5

Isothiocyanates and Processing

PEITC has been studied in laboratory experiments and human research. However, processing, heating, and the activity of plant enzymes can influence the conversion of glucosinolates into isothiocyanates. Research on raw watercress or isolated PEITC therefore cannot establish the PEITC content or effects of brewed Genuine Essiac. 6

Flavonoids and Phenolic Acids

Published analyses of watercress have identified phenolic compounds, including derivatives of quercetin and kaempferol, as well as chlorogenic and other phenolic acids. These compounds are studied as part of the plant's natural chemistry. 3

Carotenoids, Vitamins, and Minerals

Fresh watercress contains carotenoids such as lutein and beta-carotene and is known as a source of several vitamins and minerals, including vitamin K and vitamin C. Amounts present in fresh vegetables should not be assumed to be the same as those in a serving of brewed eight-herb tea. See our product-specific Nutrition Facts for finished-product information. 4

Traditional and Modern Uses of Watercress

As a Food

Watercress is widely recognized as a culinary green. Its tender leaves and stems have been used fresh and in cooked dishes. This food history is one of the characteristics that distinguishes watercress from several other Essiac ingredients.

In Traditional Botanical Preparations

Watercress appears in traditional herbal literature from several cultures. These historical uses are not evidence that watercress, or a tea containing it, has been proven to treat a health condition. 2

In Contemporary Research

Researchers continue to study the composition of watercress and its compounds in nutrition, food science, and laboratory settings. A 2025 narrative review summarizes this growing body of research while also highlighting the need to distinguish experimental findings from established clinical outcomes. 4

Why Watercress Sourcing Matters

Watercress grows in close contact with water, making growing conditions and agricultural controls important. Plant identity, water quality, harvesting, drying, and storage can all influence the quality of botanical raw material.

Important sourcing considerations include:

• Correct identification as Nasturtium officinale
• Appropriate plant part
• Growing-water and agricultural conditions
• Harvesting and handling practices
• Drying and moisture control
• Microbial quality
• Storage and traceability
• Supplier documentation and contaminant controls

How We Source Our Watercress

Genuine Essiac sources ingredients through established botanical suppliers and includes finished-product third-party testing in its quality-control program. Specific claims about farm location, growing method, organic certification, or individual-lot testing should be made only when supported by current supplier records.

Watercress in the Genuine Essiac Formula

Watercress contributes a leafy, cruciferous plant ingredient to a formula that also includes roots, bark, flowering botanicals, and brown seaweed. Its naturally occurring glucosinolates and other compounds make it botanically distinct from many of the other ingredients.

Its place in Genuine Essiac is best understood in the context of the full formula. Research on watercress alone does not establish the effects of Genuine Essiac as a whole.

Frequently Asked Questions About Watercress and Essiac

Understanding Watercress's Place in Essiac

Watercress is a distinctive component of the eight-herb formula: a leafy aquatic vegetable with a long culinary history and a well-studied family of sulfur-containing plant compounds.

Learning about its identity, chemistry, sourcing, and preparation helps explain the diversity of ingredients in Genuine Essiac. Explore all eight Essiac ingredients for more information.

Last Updated: 10/08/2026

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