Which Herbal Teas Should I Avoid?

December 19, 2025 •

4 min read

Despite the popular belief that 'natural' means safe, a 2023 study published in the Times of India warned that excessive consumption of certain herbal teas can lead to stomach problems, sleep issues, and headaches. Understanding which herbal teas should I avoid is a critical part of ensuring your wellness and preventing potential health risks.

Quick Summary

Understand the contraindications of popular herbal teas based on medical conditions, pregnancy, and potential drug interactions. This guide highlights specific teas to use with caution and identifies those with serious health risks.

Key Points

Kava and Comfrey: These teas contain highly toxic compounds that can cause severe liver damage and are best avoided by everyone.
Pregnancy Precautions: Pregnant and breastfeeding women should avoid certain teas like Licorice Root, Sage, and high-dose Chamomile due to risks of uterine contractions or other hormonal effects.
Medication Interactions: Teas like St. John's Wort, Ginkgo Biloba, and Ginseng can interfere with medications for depression, blood thinning, and diabetes, often with dangerous consequences.
Chronic Health Conditions: Individuals with high blood pressure, GERD, or specific allergies must be wary of certain teas, such as Licorice Root, Peppermint, and Chamomile.
Consult a Professional: Always talk to a doctor or pharmacist before incorporating new herbal teas into your routine, especially if you have existing health issues or are taking medication.

Dangerous Teas You Must Avoid

Certain herbal teas contain compounds that can be toxic or have severe side effects, making them unsafe for general consumption. The FDA has warned against some of these due to documented health risks.

Kava Tea: Linked to severe liver damage and has been banned in Europe and Canada. The risk is significantly increased when combined with alcohol.
Comfrey Tea: Contains pyrrolizidine alkaloids (PAs) that can cause irreversible liver damage and have been linked to cancer. It is generally advised to avoid all comfrey preparations.
Chaparral Tea: Another source of toxic compounds that can damage the liver. Its use is not recommended due to safety concerns.
Pennyroyal Tea: Highly toxic and can cause liver and nerve damage, even in small doses. It is particularly dangerous for pregnant women as it can induce abortion.

Teas to Avoid During Pregnancy and Breastfeeding

Pregnancy and breastfeeding are delicate periods where caution is paramount. Some herbs can stimulate the uterus, affect hormones, or pose risks to the developing baby.

Licorice Root Tea: Can affect blood pressure and hormone levels. Due to its estrogen-like effects, it may pose risks during pregnancy.
High-Dose Chamomile Tea: While moderate use might be considered safe by some, regular, high-dose consumption has been associated with a higher risk of preterm birth and low birth weight. It is often best to avoid it, especially in the first trimester.
Sage Tea: High doses can lead to uterine contractions and should be avoided.
Nettle Leaf Tea: Traditionally used for various ailments, nettle can alter the menstrual cycle and may contribute to miscarriage. It is advised to avoid it while pregnant or breastfeeding.
Dong Quai Tea: This herb can cause uterine contractions and increase the risk of miscarriage.

Teas That Interact with Medications

Some herbal teas contain bioactive compounds that can interfere with prescription and over-the-counter medications, altering their effectiveness or amplifying side effects.

St. John's Wort Tea: This herb has numerous drug interactions and can significantly reduce the effectiveness of birth control pills, HIV medications, statins, and others. When combined with antidepressants, it can cause a dangerous spike in serotonin levels, known as serotonin syndrome.
Ginkgo Biloba Tea: May slow blood clotting, increasing the risk of bleeding, especially for those on blood thinners like warfarin, aspirin, and NSAIDs. It can also interact with antidepressants.
Ginseng Tea: Can affect blood sugar and blood pressure. It can interact with blood thinners and metformin, increasing the risk of bleeding or hypoglycemia.
Valerian Root Tea: Known for its sedative effects, valerian can dangerously potentiate the effects of sleep aids, anti-anxiety medications (benzodiazepines), and alcohol.

Special Caution for Specific Health Conditions

Even seemingly harmless teas can be problematic for individuals with certain health issues.

High Blood Pressure: Avoid licorice root tea due to its ability to increase blood pressure. Ginseng's effect on blood pressure is unpredictable, so it should be used with caution.
GERD/Heartburn: Peppermint tea can relax the lower esophageal sphincter, potentially worsening gastroesophageal reflux disease (GERD) symptoms.
Allergies: Individuals with allergies to plants in the ragweed, marigold, or daisy family may experience allergic reactions to chamomile tea.

How to Choose Safe Herbal Teas

To ensure you're consuming herbal tea safely, follow these tips:

Always Consult a Healthcare Provider: Before starting a new herbal tea, especially if you are pregnant, breastfeeding, or have pre-existing conditions, talk to your doctor or pharmacist. They can provide guidance on potential risks and interactions.
Purchase from Reputable Brands: Quality and purity can vary widely. Buy from trusted companies known for organic, pesticide-free products and transparent sourcing.
Opt for Loose-Leaf Organic Tea: Many tea bags, especially silky sachets, can contain microplastics or be treated with chemicals. Organic loose-leaf tea brewed in a metal or glass infuser is a safer alternative.
Check Ingredients for Vague Terms: Avoid products that list "natural flavors" without specifying the source, as this can be a way to hide inferior or potentially allergenic ingredients.

Teas to Avoid: A Comparison Table


Tea Name	Primary Risk	Who Should Avoid	Safe Alternative
Kava Tea	Severe Liver Damage	Everyone, especially those with liver disease or who consume alcohol	Valerian (with caution) or Lemon Balm for sleep
Comfrey Tea	Liver Toxicity, Carcinogenic	Everyone	Ginger or Peppermint for digestion
Licorice Root Tea	High Blood Pressure, Hormone Disruption	Pregnant/Breastfeeding, Individuals with High BP, Individuals on HRT	Fennel or Ginger for digestive issues
St. John's Wort Tea	Dangerous Drug Interactions (Antidepressants, Birth Control)	Individuals taking prescription medications	Talk to a healthcare provider
Ginkgo Biloba Tea	Increased Bleeding Risk	Individuals on Blood Thinners (warfarin, aspirin, NSAIDs)	Consult a doctor for memory concerns
Ginseng Tea	Unpredictable Blood Pressure/Sugar, Bleeding Risk	Individuals with High BP, Diabetes, taking blood thinners	Consult a doctor
Pennyroyal Tea	High Toxicity, Potential Abortion	Everyone, especially pregnant women	Safe pregnancy teas (e.g., raspberry leaf in later trimesters)

Conclusion

While many herbal teas offer pleasant and beneficial properties, it is essential to be aware of the serious risks associated with others. The unregulated nature of herbal products means that individuals, especially those who are pregnant, breastfeeding, on medication, or have underlying health issues, must approach new teas with caution. Always prioritize consulting with a healthcare professional to ensure that your wellness routine does not inadvertently put your health at risk. For more information on safely choosing herbal products, resources like the Mayo Clinic's guide on herbal supplements and medications can be invaluable.

Frequently Asked Questions

No, several herbal teas can increase the risk of bleeding when combined with blood-thinning medications like warfarin or NSAIDs. These include Ginkgo Biloba, Ginger, Ginseng, and high-dose Chamomile. Always consult your doctor before consuming herbal teas if you are on blood thinners.

Some herbal teas, like Ginger (in moderation for nausea) and Peppermint, are generally considered safe during pregnancy. However, many are not, including Licorice Root, Sage, Nettle, and high-dose Chamomile. It's crucial to speak with your healthcare provider before consuming any herbal tea during pregnancy.

St. John's Wort tea should be avoided because it interacts with a wide range of medications, including birth control pills, antidepressants, and statins, making them less effective or causing severe side effects. Combining it with SSRI antidepressants can lead to a serious condition called serotonin syndrome.

Yes, several herbal teas are known to be toxic to the liver, including Kava, Comfrey, and Chaparral. These contain compounds that can cause severe and potentially irreversible liver damage, and should be strictly avoided.

Individuals with high blood pressure should avoid licorice root tea, as it can cause elevated blood pressure and sodium retention. Ginseng's effects on blood pressure can also be unpredictable. Always consult a healthcare professional.

While generally well-tolerated, peppermint tea can cause heartburn in some people, as it relaxes the muscle separating the esophagus and stomach. Individuals with GERD are often advised to avoid it.

To ensure safety, buy from reputable brands that prioritize organic ingredients and transparent sourcing. Opt for loose-leaf tea, as some modern teabags contain plastic. Check for third-party certifications and avoid products with vague terms like 'natural flavors'.