berro

What is berro?

Berro is watercress, the peppery green leaf that grows in cool running water. Its botanical name is Nasturtium officinale. In Latin America it is also called agrião and eaten in salads, soups and fresh juices.

It is a food first and a home remedy second. Cooks and home healers blend the leaves with honey or lime to make jarabe de berro, a cough syrup. The same juice is drunk as a spring tonic.

Long use in the kitchen and in home medicine is not proof that berro works. It is also not proof that larger, concentrated doses are safe. This page says that once, then sticks to what is known.

The short verdict: berro is a genuinely rich source of vitamin C and vitamin K. Small human studies show shifts in blood markers, not cures. No solid trial shows that it treats a cough, bronchitis or any disease.

One real hazard has nothing to do with the plant itself. Watercress picked wild from streams and ditches can carry liver fluke, a parasite spread by sheep and cattle. Watercress grown for shops is farmed in clean water to avoid this.

How does berro work?

No one has shown how berro acts on a cough in people. What we do know comes from its nutrients and from lab work.

Watercress is rich in glucosinolates, a group of mustard-like compounds. When you chew or crush the leaf, they turn into isothiocyanates, mainly PEITC. In cell studies, PEITC blocks enzymes that switch on cancer-causing chemicals.

In a small human study, watercress slowed the body's handling of a drug cleared by the enzyme CYP2E1. That shows the plant is active in people. It does not show that it prevents any illness.

The nutrient side is simpler and better settled. Vitamin C prevents and treats scurvy, and watercress is a good source. The leaf also carries plenty of vitamin K, which helps blood clot.

Folk use as a water pill (diuretic) rests on tradition, not on trials. Some people feel the sharp taste clears the nose. That is a sensation, not a proven effect on mucus.

What forms does berro come in?

Berro is sold mainly as fresh produce. Other forms are home-made or sit in the supplement aisle.

- Fresh bunches, sold loose or in bagged salad mixes. - Blended juice, often mixed with pineapple, orange or lime. - Jarabe de berro, a home or shop-made cough syrup with honey.

Cooked and processed forms are common as well.

- Soups and cooked dishes, a common use in Mexico, Brazil and Peru. - Dried leaf for tea. - Capsules, powders and liquid extracts.

Fresh leaf and supplements are not the same thing. A salad is food. A concentrated extract is a dose, and the cautions on this page apply more strongly to it.

Where it comes from:

Berro has a long and steady place in Latin American home medicine. Spanish settlers brought European watercress, and it spread through cool streams across the region.

Home healers treated it as a chest remedy. Leaves were pressed with honey for coughs, colds and bronchitis. The syrup was a standard winter item in many households.

It was also used as a depurativo, a so-called blood cleanser, and as a water pill for puffiness. Sailors and rural families valued it as a fresh green when little else grew.

None of this was tested in the way drugs are tested now. The record shows wide and lasting use. It does not show that the plant did what people hoped.

What does berro help with?

• Cough, colds and chest congestion: This is the best known use of berro in Latin America. The leaves were juiced with honey and taken by the spoonful. There are no good human trials of watercress syrup for cough. Honey itself does have modest trial support for night-time cough in children over one year. Much of the comfort likely comes from the honey and the warm liquid.
• Keeping up vitamin C intake: Here the ground is firm. Vitamin C prevents and treats scurvy, and fresh watercress is a good source. This is a food effect, not a drug effect. It helps only if your diet is short on vitamin C. Berro will not treat a chest infection by this route.
• Traditional 'blood cleansing' tonic: Berro juice was drunk in courses as a depurativo, a tonic meant to clear the blood. 'Blood cleansing' is not a medical idea that can be tested. Your liver and kidneys do that work. No study shows that berro helps them do it better.
• Mild fluid retention: Folk use treated berro as a water pill for swollen legs and puffiness. Human evidence is missing. Swelling can be a sign of heart, kidney or liver trouble. Treating it at home with a herb can delay a diagnosis that matters.
• Adding nutrients to everyday meals: As a salad green, berro is a sound choice. It is low in calories and high in vitamin K, vitamin C and carotenoids. This is the clearest benefit on the page. It comes from eating the plant as food, in normal meal-sized amounts.
• Claimed protection against cancer: This claim comes from lab work on PEITC, not from people. In cell and animal studies, PEITC slows the growth of some cancer cells. One small trial found less DNA damage in the white blood cells of adults who ate watercress daily. That is a marker, not a disease outcome. No study shows that berro prevents or treats cancer.

Which foods are rich in berro?

1. Fresh watercress (berro) leaves and stems
2. Watercress soup
3. Fresh watercress juice blends
4. Mixed salad bags containing watercress

Practical Tips:

Berro is a food in its own right, so the best source is the plant itself. Buy it grown for sale rather than picked from a stream.

Related greens share its mustard-like compounds. Rocket, mustard greens, radish, broccoli and cabbage all belong to the same family.

Wash fresh leaves well and use them quickly. The vitamin C falls off fast in the fridge, and faster with cooking.

What are the side effects of berro?

• Burning or peppery feeling in the mouth and throat
• Stomach upset, gas or loose stools after large raw amounts
• Heartburn, especially if you already get reflux
• Needing to pass urine more often
• Bladder or kidney irritation with large, concentrated doses
• Changes in how well warfarin works, because of the vitamin K
• Rare allergic reaction, with rash, itching or swelling
• Liver fluke infection from wild-picked watercress, with fever, right-side belly pain and yellow skin

Good to know:

In normal food amounts, berro is well tolerated by most people. The usual complaints are a hot taste and a little stomach upset.

Two problems are more serious. Wild-picked watercress can carry a liver parasite. And the vitamin K in the leaf can work against warfarin.

Concentrated juices, extracts and capsules carry more risk than a salad does, and have much less safety data behind them.

How much berro should you take?

• Recommended daily: Fresh berro is sold as a vegetable, so bunches and salad bags carry no dose at all. Typical food use is a cup or two of raw leaves in a meal. The main human study used about 85 g of raw watercress a day, roughly a large side salad. Capsule and extract labels vary a lot and are not standardised. These are the amounts seen on labels and in research, not advice for you. If you take warfarin, are pregnant, or have kidney disease, the amount you eat is a question for your doctor.
• Best time of day: Timing does not matter much for berro as food. Eat it when you would eat any salad green. Some people take cough syrup in the evening because coughs worsen at night. That is comfort, not a tested schedule.
• With or without food: Berro is food, so most people eat it with meals. That suits it well. Capsules and extracts sit better with food. The mustard-like compounds can irritate an empty stomach. Cooking it in soup is gentler on the gut than a large raw portion.
• Time to effect: Be honest with yourself here: berro may do nothing for your symptom. A cough syrup may feel soothing within minutes, mostly from the honey and warm liquid. Nutrient effects, such as topping up vitamin C, build over days to weeks of regular eating. If you expect a chest infection to clear because of berro, it will not. See a doctor instead.
• How long to take it: As an ordinary vegetable, berro can be part of your diet year-round. That is how most people in the region use it. Studies of concentrated intake ran about eight weeks. There is no evidence on taking supplements for longer than that. Home cough syrups were used for a few days during an illness, not for months.