Chamomile: tea, extracts, anxiety, sleep, allergy and interaction cautions

Two plants are sold as chamomile: German chamomile and Roman chamomile. Both are daisy-family flowers used dried in teas and as extracts. A cup of tea and a standardised extract capsule are different exposures, and most of the supplement research uses extracts, so findings do not automatically describe what you get from a teabag.

The best-known research area is anxiety. Some preliminary studies suggest a chamomile dietary supplement might help generalised anxiety disorder and the low mood that often accompanies it. The word preliminary matters. The studies are small, and they do not show chamomile to be equivalent to talking therapy or to medicines prescribed for anxiety.

If anxiety is affecting your work, sleep or relationships, your GP can discuss guided self-help, cognitive behavioural therapy and, where suitable, medicines. A herbal tea can be a pleasant part of winding down, but it is not a treatment plan.

Chamomile has a reputation as a bedtime drink. Research does not back this up strongly: a 2019 review found only one insomnia study, and it showed no benefit. The NHS advice for poor sleep centres on regular sleep times, a calm and dark bedroom, less caffeine, alcohol and screen use, and cognitive behavioural therapy for insomnia when problems persist.

For the gut, there is limited evidence that herbal combinations containing chamomile may help diarrhoea in children and colic in infants, but chamomile on its own has not been shown to work for either. A baby with colic that feeds poorly, vomits green fluid, or seems unwell needs urgent medical assessment, not a herbal tea.

Reactions to chamomile are uncommon but can be serious. They include nausea, dizziness, skin reactions and, in susceptible people, anaphylaxis. Because chamomile belongs to the same plant family as ragweed, chrysanthemums, marigolds and daisies, someone allergic to those plants has a higher chance of reacting.

• Itching of the mouth or lips, hives, wheeze, or swelling of the face after a chamomile product warrants stopping it.

• Difficulty breathing, throat tightness or collapse is an emergency: call 999.

• Eyewash and products applied near the eyes can cause irritation.

Interactions between chamomile and warfarin have been reported, along with some drugs broken down in the liver. In theory, chamomile might also add to the effect of sedatives. Anyone taking warfarin should check with their anticoagulant clinic before regularly using chamomile extracts, and everybody should list any herbal product at a medicines review or before an operation.

The NHS advises that people already on prescribed medicines check with a pharmacist before taking a herbal medicine, because those in the blood-thinning, diabetes, statin, antidepressant and contraceptive groups can be affected.

Little is known about chamomile use in pregnancy or breastfeeding, and the NHS says herbal medicines are not recommended in either situation and are not advised for children because safety data are lacking. Occasional weak tea is not the same as regular concentrated extract, but people who are pregnant should ask a midwife or pharmacist.

In the UK, many chamomile products are food supplements or teas. Some are registered as traditional herbal medicines carrying a THR mark, which signals acceptable safety and quality but not proven effectiveness.