What is Coriander?

Coriander is a kitchen herb and spice from the plant Coriandrum sativum. The dried seeds are used as a warm, citrus-like spice. The fresh leaves are sold as cilantro, Chinese parsley or dhania.

In German it is called Koriander. European folk healers used the seed mainly as a stomach remedy. They gave seed tea for wind, bloating and griping pains.

Here is the honest verdict. Centuries of food use show coriander is safe to eat in normal amounts. Long use does not show that it works as a medicine, and human trials are few and small.

So read the rest of this page with that in mind. Coriander is a pleasant, low-risk food plant. It is not a proven treatment for any illness.

How does Coriander work?

Almost everything known about how coriander acts comes from the lab, not from people.

In test tubes and in animals, coriander seed oil relaxes the muscle of the gut wall. That may explain why the tea was given for cramps and wind. The effect has not been well tested in humans.

Lab tests also show the seed oil slows the growth of some bacteria and fungi. Whether that happens inside the body is not established. The amounts used on a lab dish are far higher than anything you get from food.

Animal work suggests coriander extracts may lower blood sugar and blood fats. Human trials on this are few, small and mixed. Treat these as early leads, not as findings.

Linalool, the main part of the seed oil, calms animals in behaviour tests. That does not prove it calms people.

You may also see claims that coriander pulls heavy metals out of the body. This idea comes from a small number of animal studies and lab reports. There is no good human evidence for it.

What forms does Coriander come in?

Coriander is sold more as food than as medicine.

Common forms:

- Whole dried seed, for cooking and for tea - Ground seed powder, in curry and spice blends - Fresh leaf, sold as cilantro or Chinese parsley - Seed tea, made from crushed seed - Tinctures and liquid extracts - Capsules of ground seed or seed extract - Essential oil, for scent and flavour use - Coriander water, a traditional flavoured water

The essential oil is very concentrated. It is meant for dilution, not for swallowing by the spoon.

Where it comes from:

Coriander is one of the oldest recorded spice plants. Seeds have been found in Bronze Age sites and in Egyptian tombs.

Roman writers listed it among kitchen and healing herbs. It travelled north with Roman cooking and stayed in European gardens.

Medieval European herbals grouped it with the carminatives. These were herbs believed to move trapped wind and settle the belly. Monastic garden lists name it often.

Later European pharmacy used coriander mainly as a corrigent. That means it was added to harsh laxative mixtures to improve taste and reduce cramping. Some old gripe water recipes for infant colic used it in the same way.

Folk use also claimed it sharpened appetite and sweetened the breath. These uses are described here as history, not as advice to treat yourself.

What does Coriander help with?

• Wind, bloating and gas: This is the classic European folk use. Seed tea was given after heavy meals to move trapped wind. Lab work shows seed oil relaxes gut muscle in animals. No good human trial has tested plain coriander tea for bloating. It is a low-risk thing to try. Do not expect a reliable effect.
• Mild indigestion and stomach cramps: Old pharmacy added coriander to laxative mixes to reduce griping pain. That use was based on experience, not on trials. Human evidence is absent for coriander on its own. Any relief you feel may come from the warm drink as much as the herb.
• Poor appetite: Bitter and aromatic spices were widely used to wake up appetite before meals. Coriander was one of them. There are no modern human trials on coriander and appetite. Persistent loss of appetite needs a doctor, not a spice.
• Irritable bowel symptoms: A small number of trials have tested coriander inside mixed herbal products for irritable bowel syndrome. Some reported less pain and bloating. The products held several herbs at once. You cannot tell which herb, if any, did the work. This is weak support at best.
• Blood sugar control (claimed, unproven): Rats given coriander seed extract often show lower blood sugar. This finding is repeated across several animal studies. Human trials are few, small and not convincing. Do not use coriander in place of diabetes medicine.
• High cholesterol (claimed, unproven): Animal studies suggest coriander seed may lower blood fats. The doses used were large. There is no solid human trial showing the same thing. Diet, exercise and prescribed medicine remain the tested route.
• Sleep and mild anxiety (folk claim): Linalool, the main seed oil component, calms mice in behaviour tests. Some aromatherapy sellers build claims on this. Human studies on coriander for sleep or worry are essentially absent. Treat the claim as unproven.
• Heavy metal removal (popular claim, not supported): Internet sources often say coriander leaf pulls mercury or lead from the body. The claim traces back to a small amount of animal and lab work. No reliable human study supports it. Suspected metal poisoning is a medical matter and needs testing and treatment from a doctor.

Which foods are rich in Coriander?

1. Coriander seed, whole or ground
2. Fresh coriander leaf (cilantro)
3. Curry powder blends
4. Garam masala
5. Pickling spice mixes
6. Falafel and many Middle Eastern dishes
7. Some sausages and cured meats
8. Gin and some wheat beers

Practical Tips:

Coriander is a food in its own right, so there is no need to hunt for it in other foods.

The seed flavours spice blends, breads, pickles and drinks. The leaf is a fresh garnish across Indian, Thai, Mexican and Middle Eastern cooking.

Culinary amounts are safe for almost everyone. The exception is people with a known allergy to coriander or to related plants such as celery, fennel or caraway.

What are the side effects of Coriander?

• Allergic reaction, including rash, itching or swelling
• Hay-fever-like symptoms in people sensitive to related plants
• Skin rash from handling the fresh plant
• Sun sensitivity after the juice or oil touches skin
• Stomach upset or loose stools with large amounts
• Possible drop in blood sugar with supplement doses
• Rare but serious whole-body allergic reaction (anaphylaxis)

Good to know:

For most people coriander causes no trouble at all. It is eaten daily by millions.

The main real risk is allergy. Coriander belongs to the carrot family, alongside celery, fennel, dill, anise and caraway. People allergic to those plants, or to mugwort or birch pollen, react more often.

Most reactions are mild, such as an itchy mouth or a rash. Serious whole-body reactions have been reported but are rare.

The soapy taste some people get is not an allergy. It is a harmless difference in smell genes.

How much Coriander should you take?

• Recommended daily: Coriander is first of all a food. Most people meet it in cooking, and that needs no dose at all. These are the figures labels tend to carry, not advice for you: - Seed tea: about 1 to 2 teaspoons of crushed seed per cup - Capsules: often 1 to 3 grams of ground seed a day - Tinctures: a few millilitres a day, split into doses Essential oil labels are different. They are for scent or diluted skin use, not for swallowing. If you take medicine for diabetes or blood pressure, talk to your doctor before using supplement-strength coriander.
• Best time of day: Timing does not matter much. Folk use put the seed tea after meals, since the target was wind and fullness after eating. If you find it settling, after a meal is a sensible time. There is no evidence that any other time works better.
• With or without food: Either is fine. Seed tea was traditionally taken after eating. Capsules with food may be gentler on the stomach. Coriander in cooking is, by definition, taken with food.
• Time to effect: If coriander tea eases bloating for you, you would notice within an hour or so. It may also do nothing at all. That is a real possible outcome, and the evidence does not let us promise otherwise. The claimed blood sugar and cholesterol effects are not proven in people. Do not wait weeks expecting them to appear.
• How long to take it: There is no tested length of use, because there are no good long trials. Food use can continue for life with no known problem. Supplement use is usually short, over days or a few weeks. If you are using it for a gut symptom that has not settled in two weeks, stop guessing and see a doctor.