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Herbal Teas at a Glance: Caffeine, Evidence and Safety Table

A quick table of common herbal teas with scientific names, what is known about caffeine, how strong the evidence for the tea itself is, and the main caution each source raises.

Content last updated . This page has not been medically reviewed.

Safety first. Natural products can cause side effects and interact with medicines. Read herbal tea and extract safety before you use anything on this page.

Short answer: for most herbal teas, research on the tea itself is thin. Where trials exist they are few and small, and many results come from capsules or extracts rather than the drink. This table lists the teas for which we read an official or review source, and it says plainly when evidence for the tea itself was not found. It is information only, not medical advice, and it is not a ranking.

Safety first

  • Some entries below carry serious cautions: licorice (glycyrrhizin), senna (laxative use), comfrey (liver toxicity) and raw elderberry parts (poisonous). Read those rows before the others.
  • "Natural" does not mean safe. NCCIH says dietary supplements may interact with medicines or pose risks if you have certain medical problems or are going to have surgery. [1] Ask a pharmacist or clinician, and see how interactions work.
  • Severe allergic reaction, trouble breathing or collapse: call 911 (US). For a possible poisoning, Poison Help is 1-800-222-1222 (US). [2] See the safety quick reference.

How to read the table

  • Evidence for the tea itself is our label, based on the sources named in each row. Labels are established, promising but limited, mixed, insufficient evidence, evidence of harm and traditional use only. A result for a capsule or extract is not counted as a result for the tea. [3]
  • Caffeine: a review says herbal teas do not contain caffeine. [4] That is a general statement, and we did not find per-herb caffeine figures, so check each product's ingredient list. Blends can include true tea. [4]
  • Scientific names were checked against GBIF on 2026-10-23. [5]

Calming and sleep teas

Tea (plant, part)CaffeineEvidence for the tea itselfMain caution in the sources
Chamomile: Matricaria chamomilla (also called M. recutita), flower [6]General review statement onlyPromising but limited. One randomized trial of 80 postnatal women with poor sleep who drank chamomile tea for 2 weeks found short-term gains that were gone by 4 weeks. [7] NCCIH says studies have not produced enough reliable evidence to rate clinical usefulness. [8]Allergic reactions are more likely in people allergic to ragweed, chrysanthemums, marigolds or daisies. [8] Reported interactions with warfarin and some liver-metabolized drugs. [8]
Lemon balm: Melissa officinalis, leafGeneral review statement onlyTraditional use only (EU monograph for relief of mild mental stress and to aid sleep, based on long-standing use). [9] Trials of the tea itself: proper evidence not found in the sources we read.Use in children under 12 not established; use in pregnancy and breastfeeding not recommended for lack of data (EMA monograph). [9]
Valerian: Valeriana officinalis, root and rhizomeGeneral review statement onlyMixed. NCCIH says evidence for sleep problems is inconsistent and the American Academy of Sleep Medicine recommended against it for chronic insomnia in adults (2017). [10] The NCCIH page does not separate tea from other forms.Should not be taken with alcohol or sedatives. [10] Rare liver injury reported, mostly with other herbs. [10]
Passionflower: Passiflora incarnataGeneral review statement onlyInsufficient evidence. NCCIH describes a small amount of research on anxiety and sleep. [11]NCCIH says tea may be safe for up to 7 nights. It may interact with anesthesia drugs, and it should not be used in pregnancy. [11]
Lavender: Lavandula angustifoliaGeneral review statement onlyInsufficient evidence. NCCIH mentions initial reports of small sample size that lavender capsules or tea might reduce symptoms of depression. [12]Theoretical interaction with sedative drugs or herbs, important before surgery. [12]

Digestive and soothing teas

Tea (plant, part)CaffeineEvidence for the tea itselfMain caution in the sources
Peppermint: Mentha × piperita, leafGeneral review statement onlyInsufficient evidence. NCCIH says very little research has been done on peppermint leaf. [13] The stronger trial evidence is for enteric-coated peppermint oil capsules, a different form. [13]Peppermint oil taken alone may worsen indigestion in some people. [13] Leaf-tea cautions: proper evidence not found on that NCCIH page.
Ginger: Zingiber officinale, rhizome [14]General review statement onlyPromising but limited, and mostly for supplements. NCCIH says research suggests ginger may help nausea and vomiting of pregnancy, and that most studies tested supplements rather than foods. [14]Abdominal discomfort, heartburn, diarrhea, and mouth and throat irritation. [14]
Licorice root: Glycyrrhiza glabra, rootGeneral review statement onlyInsufficient evidence. NCCIH says there is not enough high-quality evidence to support use for any health condition. [15]Glycyrrhizin can cause serious adverse effects, including irregular heartbeat and cardiac arrest. [15] One case report: severe low potassium after about 2 liters of licorice tea daily for a year. [16]

Everyday herbal teas

Tea (plant, part)CaffeineEvidence for the tea itselfMain caution in the sources
Hibiscus: Hibiscus sabdariffa, calyxGeneral review statement onlyPromising but limited. One randomized, placebo-controlled trial of 65 adults with pre- or mildly high blood pressure found brewed hibiscus tea lowered systolic pressure over 6 weeks. [17] A Cochrane review of the broader roselle literature judged the evidence insufficient; its one included trial used capsules. [18]The trial tea lowered blood pressure. Interaction with blood pressure medicines: proper evidence not found in the sources we read for this page, so ask a pharmacist.
Rooibos: Aspalathus linearisDescribed as caffeine free [19]Promising but limited. A scoping review of 18 human publications (488 participants) found some benefit in lipids, antioxidant status and glucose, but a small number of studies and inconsistent dosing. [20]Cautions: proper evidence not found in the abstracts we read.
Dandelion: Taraxacum officinaleGeneral review statement onlyInsufficient evidence. NCCIH: no compelling scientific evidence for any health condition. [21]Theoretical interactions with antidiabetes, anticoagulant, antiplatelet and water pill drugs. [21]
Cinnamon: Cinnamomum verum and C. aromaticumGeneral review statement onlyInsufficient evidence. NCCIH says research does not clearly support use for any health condition, and often it is unclear which species or part was tested. [22]Interactions between coumarin, found in cassia cinnamon, and the liver have been reported. [22]
Turmeric: Curcuma longa, rhizomeGeneral review statement onlyInsufficient evidence. NCCIH says we do not know enough to conclude turmeric or curcumin is beneficial. [23] Studies mostly concern capsules or curcumin, not tea.Liver damage reported with highly bioavailable curcumin products (not tea). [23]
Echinacea: Echinacea purpurea and related speciesGeneral review statement onlyMixed. NCCIH says it may slightly reduce the chance of catching a cold, and it is unclear whether it shortens a cold. [24] The page does not separate tea from extracts.Allergic reactions may be severe; theoretical interaction with immunosuppressants. [24]
Hawthorn: Crataegus speciesGeneral review statement onlyInsufficient evidence. NCCIH: little or no quality evidence for most conditions. [25]The FDA warned that products labeled "tejocote root" contained yellow oleander, a toxic plant. [25]
Milk thistle: Silybum marianumGeneral review statement onlyInsufficient evidence. NCCIH: not enough high-quality evidence for definite conclusions. [26]Allergy risk in people allergic to ragweed, chrysanthemum, marigold or daisy; quality concerns about some supplements. [26]
Red clover: Trifolium pratenseGeneral review statement onlyInsufficient evidence. NCCIH: no conclusive evidence of benefit for any health condition. [27]Supplements may be unsafe in pregnancy and breastfeeding. [27]

Teas with special cautions

Tea (plant, part)CaffeineEvidence for the tea itselfMain caution in the sources
Senna leaf and laxative teas: Senna alexandrina, leafGeneral review statement onlyEstablished for one short-term use. The EMA herbal committee concluded senna leaf preparations can be used short term for occasional constipation (well-established use). [28]The EMA says long-term laxative use should be avoided, and these medicines must not be taken during pregnancy, when breastfeeding or by children under 12. [28]
Comfrey: Symphytum officinale, rootGeneral review statement onlyEvidence of harm by mouth. The EMA summary covers only skin products and says comfrey root contains pyrrolizidine alkaloids with toxic effects on the liver when taken by mouth. [29]Liver toxicity. Not a drink to seek out; read the linked page.
Elder: Sambucus nigraGeneral review statement onlyInsufficient evidence for elderberry products (NCCIH describes preliminary research on colds). [30] Elderflower tea itself: proper evidence not found on that page.Raw or unripe berries and other parts such as leaves and stem contain poisonous cyanide-producing substances. [30]

A caffeinated herbal drink and true tea for comparison

Drink (plant)CaffeineEvidence for the drink itselfMain caution in the sources
Yerba mate: Ilex paraguariensisContains caffeine: a lab study measured a mean 17.79 mg per gram of dry matter (not per cup). [31]Health effects in people: proper evidence not found in the sources we read. We read a laboratory study only.IARC classified very hot beverages as probably carcinogenic (Group 2A), and said it found no conclusive evidence for maté at temperatures that are not very hot. [32]
Green tea (Camellia sinensis), not a herbal teaContains caffeine [33]Covered in Functional Foods. NCCIH says green tea and its extracts may have a modest effect on body weight. [33]No safety concerns reported for the beverage in adults, but caffeine matters in pregnancy. [33]

Teas not in this table

We did not read an official or review source for every tea in the library, so teas such as fennel, nettle and moringa are not in this table. Find them in the A to Z directory and the research evidence snapshot. An empty row is not a sign of safety.

Frequently asked questions

Which herbal tea has the strongest evidence?

There is no single winner. Among the teas in this table, senna leaf is the one for which we read an official conclusion of well-established use, for short-term occasional constipation. [28] For tea as a drink, hibiscus and chamomile each have a small trial. [17] [7]

Are herbal teas caffeine free?

A review says herbal teas do not contain caffeine, but yerba mate does and blends can include true tea. [4] [31] The FDA notes decaffeinated teas still contain some caffeine. [34]

Which herbal teas have serious cautions?

Licorice (glycyrrhizin and heart rhythm), senna (laxative dependence and mineral imbalance), comfrey (liver toxicity) and raw elderberry parts (poisonous) stand out in the sources we read. [15] [28] [29] [30]

Does this table tell me what to drink?

No. It summarizes what sources say, and many teas have no tea-specific research. Ask a pharmacist or clinician, especially if you take medicines or are pregnant. [1]

Why do some rows say "proper evidence not found"?

It means we searched named sources, here NCCIH and EMA pages and PubMed abstracts, and found nothing usable about the tea itself. It does not mean the tea is safe or unsafe.

References
  1. National Center for Complementary and Integrative Health (NIH). Using Dietary Supplements Wisely. Read 2026-10-23.
  2. Poison Control (poison.org). Poison Control: your trusted resource. Read 2026-10-23.
  3. European Medicines Agency, HMPC. Patient Leaflet template concerning advice on the preparation of herbal teas as (traditional) herbal medicinal products by end-users, EMA/HMPC/30603/2012, adopted 20 September 2016. Read 2026-10-23.
  4. Huda HS, Majid NBA, Chen Y, et al. Exploring the ancient roots and modern global brews of tea and herbal beverages: A comprehensive review. Food Sci Nutr. 2024. PubMed 39479640. Read 2026-10-23.
  5. GBIF Secretariat. GBIF Backbone Taxonomy species match. Names queried 2026-10-23 (accepted: Matricaria chamomilla L., Melissa officinalis L., Valeriana officinalis L., Passiflora incarnata L., Lavandula angustifolia Mill., Mentha x piperita L., Zingiber officinale Roscoe, Glycyrrhiza glabra L., Taraxacum officinale, Hibiscus sabdariffa L., Aspalathus linearis (Burm.f.) R.Dahlgren, Sambucus nigra L., Senna alexandrina Mill., Symphytum officinale L., Ilex paraguariensis A.St.-Hil., Camellia sinensis (L.) Kuntze, Cinnamomum verum J.Presl, Curcuma longa L., Echinacea purpurea (L.) Moench, Crataegus monogyna Jacq., Silybum marianum (L.) Gaertn., Trifolium pratense L.).
  6. European Medicines Agency, HMPC. Matricariae flos (matricaria flower): herbal medicinal product, summary. Read 2026-10-23.
  7. Chang SM, Chen CH. Effects of an intervention with drinking chamomile tea on sleep quality and depression in sleep disturbed postnatal women: a randomized controlled trial. J Adv Nurs. 2016. PubMed 26483209 (abstract read 2026-10-23).
  8. National Center for Complementary and Integrative Health (NIH). Chamomile: Usefulness and Safety. Read 2026-10-23.
  9. European Medicines Agency, HMPC. Community herbal monograph on Melissa officinalis L., folium, EMA/HMPC/196745/2012. Read 2026-10-23.
  10. National Center for Complementary and Integrative Health (NIH). Valerian: Usefulness and Safety. Read 2026-10-23.
  11. National Center for Complementary and Integrative Health (NIH). Passionflower: Usefulness and Safety. Read 2026-10-23.
  12. National Center for Complementary and Integrative Health (NIH). Lavender: Usefulness and Safety. Read 2026-10-23.
  13. National Center for Complementary and Integrative Health (NIH). Peppermint Oil: Usefulness and Safety. Read 2026-10-23.
  14. National Center for Complementary and Integrative Health (NIH). Ginger: Usefulness and Safety. Read 2026-10-23.
  15. National Center for Complementary and Integrative Health (NIH). Licorice Root: Usefulness and Safety. Read 2026-10-23.
  16. Guarneri C, et al. Pseudo-Hyperaldosteronism After the Ingestion of Licorice Tea: A Case Report. Cureus. 2026. Single case. PubMed 42367449 (abstract read 2026-10-23).
  17. McKay DL, Chen CY, Saltzman E, Blumberg JB. Hibiscus sabdariffa L. tea (tisane) lowers blood pressure in prehypertensive and mildly hypertensive adults. J Nutr. 2010. PubMed 20018807 (abstract read 2026-10-23).
  18. Pattanittum P, et al. Roselle for hypertension in adults. Cochrane Database Syst Rev. 2021. PubMed 34837382 (abstract read 2026-10-23).
  19. Pretorius L, et al. Translation of preclinical ethnomedicine data in LMICs: the example of rooibos. Front Pharmacol. 2023. PubMed 38174224 (abstract read 2026-10-23).
  20. Afrifa D, et al. The health benefits of rooibos tea in humans (Aspalathus linearis): a scoping review. J Public Health Afr. 2023. PubMed 38204815 (abstract read 2026-10-23).
  21. National Center for Complementary and Integrative Health (NIH). Dandelion: Usefulness and Safety. Read 2026-10-23.
  22. National Center for Complementary and Integrative Health (NIH). Cinnamon: Usefulness and Safety. Read 2026-10-23.
  23. National Center for Complementary and Integrative Health (NIH). Turmeric: Usefulness and Safety. Read 2026-10-23.
  24. National Center for Complementary and Integrative Health (NIH). Echinacea: Usefulness and Safety. Read 2026-10-23.
  25. National Center for Complementary and Integrative Health (NIH). Hawthorn: Usefulness and Safety. Read 2026-10-23.
  26. National Center for Complementary and Integrative Health (NIH). Milk Thistle: Usefulness and Safety. Read 2026-10-23.
  27. National Center for Complementary and Integrative Health (NIH). Red Clover: Usefulness and Safety. Read 2026-10-23.
  28. European Medicines Agency, HMPC. Sennae folium (senna leaf): herbal medicinal product, summary for the public, EMA/697536/2018, first published 28 July 2020. Read 2026-10-23.
  29. European Medicines Agency, HMPC. Symphyti radix (comfrey root): herbal medicinal product, summary. Page undated in the text we read. Read 2026-10-23.
  30. National Center for Complementary and Integrative Health (NIH). Elderberry: Usefulness and Safety. Read 2026-10-23.
  31. Najman K, et al. Changes in the Physicochemical and Bioactive Properties of Yerba Mate Depending on the Brewing Conditions. Molecules. 2024. Laboratory analysis. PubMed 38893465 (abstract read 2026-10-23).
  32. International Agency for Research on Cancer (WHO). IARC Monographs evaluate drinking coffee, maté, and very hot beverages, press release no. 244, 15 June 2016. Read 2026-10-23.
  33. National Center for Complementary and Integrative Health (NIH). Green Tea: Usefulness and Safety. Read 2026-10-23.
  34. U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine is Too Much? Consumer update. Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.