Herbal Tea & Extract Safety
Herbal tea and extract safety: licorice and heart or blood pressure risk, senna laxative teas, medicine interactions, allergy, pregnancy, alcohol in tinctures, and what is not known.
Content last updated . This page has not been medically reviewed.
A tea is not harmless just because it is diluted or sold as a food. [1] This page summarizes risks we could source. It is education, not personal advice. For plant background and more herbs, see Herb safety & interactions.
Cautions by tea (NIH and review sources)
| Tea | Main cautions | Interactions named |
|---|---|---|
| Licorice root | Glycyrrhizin can cause irregular heartbeat and cardiac arrest, especially in large or long-term use, and with high salt intake, hypertension, or heart or kidney conditions; large amounts unsafe in pregnancy [2] | Corticosteroids [2] |
| Senna (laxative / slimming teas) | Dependence and loss of normal bowel activity with frequent use; not for more than 1 week without a doctor; care in pregnancy, breastfeeding and older age [3] | Some products affect how other medicines work; ask a pharmacist [3] |
| Chamomile | Allergy (ragweed family), possible severe reactions; estrogen-like effects [4] | Warfarin, some liver-processed medicines, birth control pills; theoretical with sedatives [4] |
| Hibiscus | Lowers blood pressure; minor liver enzyme rise; long-term safety needs monitoring [5] | Not detailed in sources we read; ask if you take blood pressure medicine |
| Dandelion | Allergy possible; larger amounts less studied [6] | Theoretical with antidiabetes, anticoagulant, antiplatelet and diuretic drugs [6] |
| Peppermint tea | Large amounts long-term unknown [7] | Not detailed [7] |
| Ginger | Heartburn, diarrhea, mouth irritation [8] | Not detailed [8] |
| Marshmallow root | May delay absorption of other medicines; EU monograph says separate by 1/2 to 1 hour [9] | Other medicines (absorption) [9] |
| Nettle | Not where reduced fluid intake is advised (severe cardiac or renal disease); stomach upset and skin reactions [10] | None reported [10] |
| Fennel | Allergy to Apiaceae plants (celery, dill, aniseed), mugwort pollen cross-reactivity; estragole limit for young children [11] | None reported [11] |
| Peppermint tea (EU monograph) | Worsens acid reflux and heartburn; caution with gallstones and bile problems; not under 4 [12] | None reported [12] |
| Lemon balm, passionflower, lavender, elderflower | Pregnancy and breastfeeding use not recommended (safety not established); not under 12 [13][14][15][16] | None reported (lemon balm: no data) |
| Green tea (true tea) | Caffeine; extract capsules linked to liver injury [17] | Nadolol, atorvastatin, raloxifene [17] |
"Not detailed" means the source we read does not list one, not that none exist.
Documented vs theoretical
Some interactions are reported in people (chamomile and warfarin; licorice and corticosteroids), and others are theoretical (dandelion with several drug classes; chamomile with sedatives). [4][2][6] Treat both as reasons to ask a pharmacist.Laxative and detox teas
See the claim check. Senna dependence and detox-tea hyponatremia are documented. [3][18]Pregnancy, breastfeeding and children
EU monographs for lemon balm, passionflower, valerian, nettle, lavender, elderflower, fennel and peppermint say safety in pregnancy and breastfeeding has not been established and use is not recommended. [13][14][19][10][15][16][11][12] Many supplements have not been tested in pregnant women, nursing mothers or children. [1] Specific cautions: large licorice amounts in pregnancy are unsafe; ask about senna; chamomile, dandelion and hibiscus have little sourced information. [2][3] Ask a pharmacist or clinician before giving any herbal drink to a baby or child.Alcohol in tinctures
Alcohol-based extracts contain alcohol; see Extracts & tinctures. If you cannot have alcohol, ask a pharmacist.Sedating herbs and alcohol
NIH says valerian should not be taken with alcohol or sedatives. [20] See the Valerian guide.Contamination and misidentification
What is on a supplement label may not be what is in the product, and the FDA has found prescription drugs in products sold as supplements. [1] Do not make tea from a wild plant unless an expert has identified it; some plants are poisonous.When to stop and get help
Stop and contact a clinician for a rash, swelling, trouble breathing, yellow skin or eyes, palpitations, fainting or severe stomach pain. [1] In the US, Poison Control is 1-800-222-1222; call 911 for collapse, seizure or trouble breathing. [21]Frequently asked questions
Can herbal tea interact with my medicine?
Yes, some can. Licorice with corticosteroids and chamomile with warfarin are reported. Ask a pharmacist. [2][4]
Is licorice tea safe?
It has cardiac and blood pressure cautions. See the licorice root tea guide. [2]
References
- National Center for Complementary and Integrative Health (NIH). Using Dietary Supplements Wisely. Page last updated January 2019.
- National Center for Complementary and Integrative Health (NIH). Licorice Root: Usefulness and Safety. Page dated April 2025.
- MedlinePlus Drug Information. Senna. National Library of Medicine.
- National Center for Complementary and Integrative Health (NIH). Chamomile: Usefulness and Safety. Page last updated November 2024.
- Norouzzadeh M, et al. Efficacy and safety of Hibiscus sabdariffa in cardiometabolic health: An overview of reviews and updated dose-response meta-analysis. Complement Ther Med. 2025;89:103135. PubMed 39870328.
- National Center for Complementary and Integrative Health (NIH). Dandelion: Usefulness and Safety. Page last updated November 2024.
- National Center for Complementary and Integrative Health (NIH). Peppermint Oil: Usefulness and Safety. Page last updated May 2025. (Also describes peppermint leaf and tea.)
- National Center for Complementary and Integrative Health (NIH). Ginger: Usefulness and Safety. Page last updated February 2025.
- European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). Althaeae radix (marshmallow root) - herbal medicinal product (public summary) and EU herbal monograph, EMA/HMPC/436679/2015.
- European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). Urticae folium (nettle leaf) - herbal medicinal product (public summary) and EU herbal monograph, EMA/HMPC/508015/2007.
- European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). Foeniculi dulcis fructus (sweet fennel fruit) - herbal medicinal product (public summary) and EU herbal monograph, EMEA/HMPC/372839/2016. Final, revision 1, dated 31 January 2024.
- European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). Menthae piperitae folium (peppermint leaf) - herbal medicinal product (public summary) and EU herbal monograph, EMA/HMPC/572705/2014.
- European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). Melissae folium (melissa leaf) - herbal medicinal product (public summary) and EU herbal monograph, EMA/HMPC/196745/2012. Monograph compiled 14 May 2013.
- European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). Passiflorae herba (passion flower) - herbal medicinal product (public summary) and EU herbal monograph, EMA/HMPC/669740/2013.
- European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). Lavandulae flos (lavender flower) - herbal medicinal product (public summary) and EU herbal monograph, EMA/HMPC/734125/2010.
- European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). Sambuci flos (elder flower) - herbal medicinal product (public summary) and EU herbal monograph, EMA/HMPC/611512/2016. Monograph dated 27 March 2018.
- National Center for Complementary and Integrative Health (NIH). Green Tea: Usefulness and Safety. Page last updated February 2025.
- Gillett G, et al. Acute Severe Hyponatremia Following Use of "Detox Tea". Cureus. 2021;13(3):e14184. PubMed 33936895. A single case report (one 51-year-old woman).
- European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). Valerianae radix (valerian root) - herbal medicinal product (public summary) and EU herbal monograph, EMA/HMPC/150848/2015.
- National Center for Complementary and Integrative Health (NIH). Valerian: Usefulness and Safety. Page last updated May 2025.
- Poison Control (America's Poison Centers). poison.org. Help line 1-800-222-1222; online tool; call 911 for collapse, seizure, trouble breathing or inability to wake.
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.