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Watercress is a peppery aquatic green from the cabbage and mustard family that grows in shallow, flowing water. In USDA data it has only about 11 calories per 100 grams yet supplies large shares of the Daily Values for vitamin K and vitamin C, and a 2014 paper in a CDC journal ranked it first of 47 fruits and vegetables for nutrients per calorie. This guide covers watercress nutrition, what the small trials on watercress benefits actually measured, how to eat watercress, and two safety points: warfarin and the liver fluke risk of wild-picked plants.
Peptide Labs does not sell watercress or watercress products. This article is general nutrition information, not medical advice.
Key Takeaways
- Watercress (Nasturtium officinale) is a cruciferous green, related to arugula, cabbage and mustard.
- Per 100 grams it has about 11 calories and supplies vitamin K and vitamin C in USDA data.
- A 2014 nutrient density study ranked watercress first of 47 foods for nutrients per calorie.
- Human trials are small and measured blood markers, not disease outcomes.
- Raw watercress from wild or unprotected water can carry Fasciola liver fluke larvae, per CDC.
What is watercress?
Watercress, Nasturtium officinale, is a perennial plant that grows in springs, streams and purpose-built beds fed by clean running water. Despite the scientific name, it is not related to the garden nasturtium flower. It belongs to the Brassicaceae family with broccoli, kale, horseradish and our sibling green, arugula, and like them it contains glucosinolates, the sulfur compounds behind its peppery taste. It is sold in bunches, in bags or as living plants with roots attached, and the small round leaves and tender stems are both eaten.
Watercress nutrition facts from USDA
The table uses the USDA FoodData Central SR Legacy entry Watercress, raw (FDC 170068). USDA lists one cup of chopped watercress as 34 grams. Percentages use the FDA Daily Values printed on Nutrition Facts labels.
| Watercress, raw (FDC 170068) | Per 100 g | % DV | Per cup chopped, 34 g | % DV |
|---|---|---|---|---|
| Calories | 11 | 4 | ||
| Protein | 2.3 g | 5% | 0.8 g | 2% |
| Fiber | 0.5 g | 2% | 0.2 g | 1% |
| Vitamin K | 250 mcg | 208% | 85 mcg | 71% |
| Vitamin C | 43 mg | 48% | 15 mg | 16% |
| Vitamin A | 160 mcg RAE | 18% | 54 mcg RAE | 6% |
| Calcium | 120 mg | 9% | 41 mg | 3% |
| Potassium | 330 mg | 7% | 112 mg | 2% |
| Magnesium | 21 mg | 5% | 7 mg | 2% |
| Manganese | 0.24 mg | 11% | 0.08 mg | 4% |
| Folate | 9 mcg DFE | 2% | 3 mcg DFE | 1% |
Watercress is about 95% water, so it is among the lowest-calorie foods in the USDA database. Its standout nutrient is vitamin K: a single cup supplies about 71% of the Daily Value. It also adds vitamin C, covered in our guide to vitamin C sources, and carotenoids. USDA lists lutein plus zeaxanthin for watercress, a topic in our lutein guide. It is low in fiber and folate compared with spinach, so it works well alongside other vegetables rather than in place of them.
Watercress compared with other greens
Per 100 grams of raw leaves, USDA data show how watercress stacks up:
| Per 100 g, raw (USDA FDC ID) | Calories | Vitamin K (% DV) | Vitamin C (% DV) | Calcium (% DV) | Folate (% DV) |
|---|---|---|---|---|---|
| Watercress (170068) | 11 | 208% | 48% | 9% | 2% |
| Arugula (169387) | 25 | 91% | 17% | 12% | 24% |
| Spinach (168462) | 23 | 402% | 31% | 8% | 49% |
| Kale (168421) | 35 | 325% | 104% | 20% | 16% |
| Romaine (169247) | 17 | 85% | 4% | 3% | 34% |
Kale and spinach carry more vitamin K per 100 grams, kale has more vitamin C, and spinach and arugula have far more folate. Watercress has the fewest calories of the group. Our kale guide and our guide to salad and cooking greens compare more greens per cup.
Watercress benefits: what the research shows
Watercress often appears at the top of nutrition lists because of one study. In 2014, a paper in Preventing Chronic Disease, a CDC journal, scored 47 fruits and vegetables by the average share of the Daily Value for 17 nutrients per 100 calories. Watercress scored 100, the maximum, followed by Chinese cabbage, chard, beet greens and spinach; arugula scored about 38. That ranking is about nutrients per calorie, which favors very watery greens, and it says nothing about health outcomes. Our superfoods guide explains why such labels need context.
Human trials of watercress are small and measured blood markers:
- DNA damage markers (2007): a randomized crossover trial in 60 healthy adults, half of them smokers, added raw watercress to their usual diet for eight weeks. Basal DNA damage in white blood cells fell by 17% and blood lutein and beta-carotene rose, with larger changes in smokers. These are biomarkers, not proof of lower disease risk.
- Exercise study (2013): 10 healthy young men ate watercress before exhausting exercise, once and over eight weeks; markers of exercise-related DNA damage and lipid oxidation were lower than in the control phase.
- Systematic review (2025): seven small randomized trials with 302 people and an average follow-up of 39 days found that most antioxidant and inflammation markers improved and that watercress was well tolerated. The authors noted the short follow-up.
The honest summary: watercress is a very low-calorie green with a lot of vitamin K and useful vitamin C, and small trials show changes in blood markers. Claims that it cleanses the body, reverses disease or speeds weight loss are not supported. Our guide to antioxidant foods explains what antioxidant markers can and cannot tell us.
Watercress and warfarin: keep intake steady
Because watercress is rich in vitamin K, it matters for people taking warfarin (Coumadin). The NIH Office of Dietary Supplements says warfarin users need a consistent intake of vitamin K from food and supplements, since sudden changes can raise or lower the drug’s effect, and MedlinePlus advises eating consistent amounts of vitamin K foods from week to week and talking to your doctor before changing your diet. Keep portions steady rather than avoiding the green. Our guide to vitamin K in foods lists the richest greens.
Wild watercress and liver flukes
Watercress grows where water flows, and that creates one food safety risk worth knowing. According to the CDC, Fasciola is a liver fluke that can infect the liver and bile ducts of people and animals, and people can be infected by eating raw watercress or other freshwater plants contaminated with its larvae, or through contaminated water. The parasite is common in sheep and cattle, and its larvae develop in water snails, so plants picked from streams near grazing land carry the most risk. A 1982 case report described wild watercress as the usual source of human infection. Commercial beds are not automatically safe either: in 2002, 18 cases in northern France were traced to raw watercress from one grower whose beds were not protected from the snail host.
- Do not eat raw watercress picked from the wild, especially near pastures with sheep or cattle.
- Choose watercress from grocers that source from controlled, commercial growers, and wash it well.
- Cooking watercress in soups or stir-fries is the traditional way it is eaten in many regions.
- Fever, pain under the right ribs or unexplained illness after eating wild greens is a reason to see a clinician and mention it. Herbal parasite cleanses are not a substitute; our parasite cleanse guide explains why.
How to eat watercress
- Raw: add the leaves and tender stems to salads and sandwiches, or blend into a green sauce. A little oil helps absorb its fat-soluble vitamins.
- Cooked: watercress soup is a classic, and it wilts quickly into eggs, noodles or stir-fries, which mellows its bite.
- Storage: keep bunches cold, stems in a glass of water or wrapped in a damp towel, and use within a few days; discard yellow or slimy leaves.
- Allergy: watercress is not one of the nine major food allergens that US labels must declare, but any plant can cause a reaction. Hives, swelling or breathing trouble needs urgent care; for unclear symptoms, see an allergist.
Frequently Asked Questions
Is watercress healthy?
Watercress is a very low-calorie cruciferous green that supplies a lot of vitamin K and useful vitamin C in USDA data. Human trials are small and measured blood markers.
How many calories are in watercress?
About 4 calories per chopped cup (34 grams) and 11 calories per 100 grams, in USDA data.
Why is watercress called the most nutrient-dense vegetable?
A 2014 paper in a CDC journal ranked it first of 47 foods for nutrients per 100 calories. That ranking favors very watery, low-calorie greens.
Can you eat watercress raw?
Yes, store-bought watercress is commonly eaten raw after washing. Do not eat raw wild-picked watercress, which can carry liver fluke larvae.
Is watercress the same as arugula?
No. Both are peppery greens in the cabbage family, but watercress is an aquatic plant and arugula grows in soil. Their nutrient profiles differ.
Can I eat watercress if I take warfarin?
Usually yes, but keep your intake of vitamin K foods consistent and talk to your clinician before making diet changes.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a food allergy. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Arugula: Nutrition, Benefits and How It Compares to Spinach, Leafy Greens: USDA List of Dark Greens, Spinach vs Kale and Tips, Foods High in Vitamin C: USDA List of Fruits and Vegetables.