What is Linden?

Linden is the dried flower of the basswood tree, Tilia americana. The small cream-coloured flowers come attached to a pale leaf-like wing, and both are dried together. In French shops the same kind of tea is sold as tilleul.

People drink it for two main reasons. One is as a calm, mild evening tea for stress or restless sleep. The other is as a hot drink during a cold, to feel warm and sweat a little.

Here is the honest verdict on the evidence. There are almost no human trials on linden, and none of real size on this American species. Long use in folk medicine is not proof that it works, and it is not proof that it is safe.

That said, linden flower tea is a low-risk drink for most healthy adults. The main risks are allergy and the risk of using tea in place of care you actually need.

How does Linden work?

No one has shown in people how linden works, or whether it works at all. What follows is the proposed mechanism, and it rests on lab and animal work.

Linden flowers are rich in mucilage, a slippery plant gum. A warm, gummy drink can physically coat a sore throat. That part is simple and believable, but it is comfort, not healing.

Extracts of Tilia americana have calmed mice in lab tests. In test-tube work, some linden flavonoids bind to the GABA-A receptor, the same brain target used by sedative drugs. Whether any of this happens in a person who drinks a cup of tea is not known.

The old "sweating out a fever" idea has not been tested properly. A hot drink of any kind makes you flush and sweat, so the flower may add nothing.

What forms does Linden come in?

Linden is sold in a few plain forms:

- Loose dried flower and bract, for brewing as tea. This is the traditional form and the most common one.

- Tea bags, often blended with chamomile, lemon balm or mint.

- Tinctures, which are alcohol-based liquid extracts.

- Capsules and dry extracts, which are less common.

- Linden honey, made by bees from the flowers. This is an ordinary food, not a remedy.

Most European products use Tilia cordata or Tilia platyphyllos. Tilia americana is the usual North American source and is the species on this page. They are close relatives but have not been compared head to head in people.

Where it comes from:

Linden tea has a long record in both Europe and North America. European use of tilleul as an evening and cold-season drink goes back centuries.

In American folk medicine, basswood flowers were brewed during fevers and colds. The flowers were valued for making a patient warm and sweaty, which was then thought to help a fever break.

Eclectic physicians of the 19th and early 20th century listed Tilia for nervous restlessness, cough and mild stomach upset. They treated it as a gentle, low-power herb rather than a strong one.

Several Native American groups used basswood bark and flowers, including as a cough remedy. These records describe what was done; they do not show that it worked.

What does Linden help with?

• Restlessness and mild nervous tension: This is linden's best-known use and its most-studied one, though the bar is low. Eclectic and folk writers called it a gentle nerve-settler for people who were wound up. The lab work is suggestive. Tilia americana extracts calmed and sedated mice, and linden flavonoids bind sedative receptors in test-tube studies. There are no good human trials. Any calm you feel may come from the warm drink and the pause, not the plant.
• Trouble settling to sleep: Linden is a traditional bedtime tea across Europe and North America. The claim is that it helps you unwind, not that it knocks you out. No trial has measured whether linden helps people fall asleep or stay asleep. The animal sedation data does not carry over to a cup of tea. It may do nothing for your sleep. If sleep problems last more than a few weeks, that needs a doctor, not a tea.
• Common cold and sore throat: Linden will not shorten a cold, and nothing suggests it fights the virus. Its role is comfort. The European Medicines Agency allows linden flower to be sold as a traditional remedy for colds. That label is based on long use alone, not on trial results. The mucilage coats a raw throat, and any hot drink eases that feeling. This is real relief, but it is short-lived and modest.
• Cough: Folk and Eclectic use included linden for dry, tickly coughs. The reasoning was the soothing gum content. Human evidence is essentially absent. Warm fluids in general can ease a dry cough for a while. A cough with fever, blood, chest pain or breathlessness is not a tea problem. Get it looked at.
• Fever comfort: The old use was to make a feverish person sweat. This idea comes from a theory of fever that medicine no longer uses. No study shows that linden lowers a fever or shortens an illness. A hot drink alone makes most people flush and sweat. Do not treat a high or lasting fever with tea. In a baby, an older adult, or anyone with a weak immune system, fever needs medical care.
• Mild indigestion: Some Eclectic texts listed linden for a nervous, upset stomach. It was a minor use even then. There is no human evidence for it. The mucilage may be mildly soothing, but this has not been tested. Ongoing stomach pain, heartburn or changed bowel habits need a proper diagnosis.

Which foods are rich in Linden?

Linden is not a nutrient, so no food supplies it. Linden honey is made by bees working the flowers and is eaten as a normal food. It has not been shown to carry the effects claimed for the tea.

What are the side effects of Linden?

• Allergic reaction, including rash, itching or swelling
• Itchy mouth or throat in people allergic to tree pollen
• Mild drowsiness
• Nausea from very strong brews
• Sweating and mild fluid loss when drunk hot and often
• Skin rash from handling the fresh flowers

Good to know:

Side effects are uncommon, and most are mild. Linden tea is widely drunk as an ordinary beverage.

Allergy is the main real risk. Linden pollen can trigger hay-fever-type reactions, and contact with the flowers has caused skin rashes in people who pick them.

A true allergic reaction is rare but serious. Swelling of the lips, tongue or throat, or trouble breathing, is an emergency.

How much Linden should you take?

• Recommended daily: Linden is a food-grade herbal tea, so a general amount can be described. This is what labels and herbal monographs typically carry, not advice for you. Tea labels commonly list about 1.5 to 2 grams of dried flower per cup, roughly one heaped teaspoon. Two to four cups a day is the usual stated range for adults. Tincture and capsule strengths vary a lot between brands. Follow the product label and check with a pharmacist if you take other medicines. No amount has been tested for a health effect in people. More is not better here.
• Best time of day: Timing is flexible and no study backs any particular hour. Most people drink it in the evening, because the calming use fits bedtime. Some find it mildly drowsy, so an evening cup suits that better. For a cold or sore throat, people drink it whenever the throat feels raw.
• With or without food: Food makes no known difference to linden tea. A few people get mild nausea from a very strong brew on an empty stomach. If that happens, have it after food or make it weaker.
• Time to effect: The throat-soothing feel arrives while you drink it and fades within an hour. Any calming effect, if it happens at all, would be noticed within 30 to 60 minutes. It may do nothing for you. No trial has shown a measurable effect in people, so a flat result is an honest possibility.
• How long to take it: Linden tea is usually taken for a short run, over a few days of a cold or a stressful week. European traditional-use labels advise seeing a doctor if symptoms last more than about a week. No one has studied long-term daily use. There is an old, unconfirmed claim that very heavy, years-long use strains the heart; it has never been proven or ruled out. If you find yourself drinking it daily for months to cope, that is worth raising with a doctor.