When should you not drink herbal tea?: A comprehensive guide

October 9, 2025 •

5 min read

According to the National Center for Complementary and Integrative Health (NCCIH), it's important to recognize that 'natural' doesn't always mean safe. Therefore, knowing when should you not drink herbal tea is crucial for your health, particularly if you are pregnant, have existing health conditions, or are taking prescription medications.

Quick Summary

This guide details specific situations where drinking herbal tea may be harmful, including interactions with medications like blood thinners, potential risks during pregnancy, and specific contraindications for certain health conditions. It also covers the importance of checking for allergies to ingredients and highlights the risks associated with certain unregulated herbs.

Key Points

Blood Thinners and Anticoagulants: Avoid herbal teas containing ingredients like ginkgo biloba, chamomile, turmeric, and ginger if you are on blood-thinning medication, as they can increase the risk of bleeding.
Pregnancy and Breastfeeding: Exercise extreme caution with herbal teas during pregnancy, as many are not well-researched for safety and some can stimulate uterine contractions or affect fetal development.
Specific Health Conditions: Individuals with liver or kidney disease, iron deficiency, or gastrointestinal issues should consult a doctor before consuming herbal teas, as some can worsen these conditions or cause organ toxicity.
Medication Interactions: Inform your healthcare provider about all herbal teas you consume, as many can interfere with the effectiveness of prescription drugs, including antidepressants and statins.
Allergy Risk: Be aware of potential allergic reactions, particularly if you have sensitivities to plants in the daisy family, as some teas like chamomile and echinacea can trigger symptoms.

Herbal tea safety considerations

Herbal teas, or tisanes, are popular for their flavor and a range of purported health benefits, such as promoting relaxation or aiding digestion. They are made from a variety of botanicals, including leaves, flowers, fruits, and roots. However, the active compounds in these plants can have powerful effects on the body and may not be suitable for everyone. While most herbal teas are safe in moderation for the general population, specific health circumstances, allergies, and interactions with medication necessitate caution or complete avoidance. The potential for contaminants like heavy metals or other unwanted compounds in unregulated products also poses a risk, particularly for vulnerable populations.

Potential interactions with medications

Many herbal teas contain bioactive compounds that can interact with prescription and over-the-counter medications, altering their effectiveness or increasing the risk of adverse side effects. These interactions are a significant reason to exercise caution and consult a healthcare provider.

Blood thinners (anticoagulants): Certain herbal teas can increase the risk of bleeding when combined with blood-thinning medications like warfarin. Ingredients such as chamomile, ginkgo biloba, turmeric, and ginger can interfere with blood clotting. Green tea, which contains vitamin K, can also make warfarin less effective.
Antidepressants: St. John's wort, often used for mood support, can cause dangerous interactions with antidepressants, particularly selective serotonin reuptake inhibitors (SSRIs), leading to serotonin syndrome.
Blood pressure medications: The caffeine in green tea and other true teas can increase blood pressure, which may interfere with the effectiveness of blood pressure medications.
Statins: Some herbal teas, such as ginkgo biloba and St. John's wort, can interfere with statin metabolism, potentially leading to liver damage.

Contraindications during pregnancy and breastfeeding

Pregnant and breastfeeding individuals should be extremely cautious with herbal teas. Many herbs have not been sufficiently studied for safety during these critical periods, and some are known to pose significant risks. The concentration of herbs in tea is higher than in food, increasing the potential for harm.

Miscarriage or premature labor: Some teas can stimulate uterine contractions, which could lead to miscarriage or preterm labor. Herbs to avoid include ginseng, pennyroyal, wormwood, and large amounts of parsley.
Birth defects: Certain herbs, like ginseng, have been linked to potential risks during fetal development and should be avoided, especially in the first trimester.
Contamination risk: The lack of regulation for herbal teas means they can be contaminated with other unwanted compounds or herbs, which is particularly risky for pregnant individuals.
Herbal teas considered unsafe or debated: Chamomile tea, for example, has conflicting information regarding safety during pregnancy, with some studies suggesting potential risks like preterm delivery. Other herbs, such as raspberry leaf and peppermint, are often debated for their use in early pregnancy due to their effects on the uterus.

Allergies and sensitivities

Even if an herbal tea is generally safe, it can trigger an allergic reaction or unpleasant side effects in some individuals. An allergic response can range from mild symptoms like hives to severe, life-threatening anaphylactic shock.

Plant-specific allergies: People with allergies to specific plants, such as those in the daisy or ragweed family, may react to teas containing chamomile or echinacea.
Symptoms: Reactions can include skin irritation, nausea, vomiting, headaches, and asthma symptoms.
Severe reactions: In rare cases, anaphylaxis can occur. It is crucial to monitor your body's response, especially when trying a new tea.

Certain health conditions and excessive intake

For those with certain health issues, or when consumed in excess, herbal tea can exacerbate problems. The “natural is safe” myth is particularly dangerous when dealing with existing conditions.

Liver and kidney disease: Certain herbs, including comfrey and chaparral, can be toxic to the liver, especially when consumed regularly or in large amounts. Excessive intake of other herbal teas has been linked to kidney problems.
Iron deficiency: The tannins found in some teas, particularly green tea, can inhibit iron absorption, which is problematic for individuals with anemia or low iron levels.
Gastrointestinal issues: Tannins can also irritate the digestive tissue, potentially causing nausea or stomach ache, especially when consumed on an empty stomach. For those with GERD, the acidity of some teas might worsen symptoms.

Comparison of popular herbal teas and their associated risks


Herbal Tea	Common Use	Primary Risk Factors	Who Should Avoid or Exercise Caution	Potential Interaction with Medications
Chamomile	Relaxation, sleep aid	Potential blood-thinning effect; possible allergic reaction in those sensitive to ragweed	People on blood thinners; pregnant women (debate); individuals with ragweed allergies	Warfarin, Cyclosporine
Ginkgo Biloba	Memory, cognition	Slows blood clotting; possible serotonin syndrome	People on blood thinners or antidepressants; individuals with liver conditions	Warfarin, Aspirin, SSRIs, NSAIDs
Ginger	Nausea, digestion	Increases bleeding risk	People on blood thinners	Warfarin, Aspirin
St. John's Wort	Mood support, depression	Reduces effectiveness of many medications; serotonin syndrome risk with antidepressants	People on birth control, HIV medications, blood thinners, or antidepressants	Oral Contraceptives, Antidepressants, Warfarin, HIV drugs
Licorice Root	Digestive aid, respiratory health	Can increase blood pressure and potassium loss	Individuals with high blood pressure, heart disease, or kidney disease	Diuretics, Blood Pressure Medication
Kava	Stress relief	Potential liver toxicity	Individuals with liver disease, taking sedatives, antidepressants, or anticonvulsants	Sedatives, Anticonvulsants, Antidepressants
Peppermint	Digestion, congestion	Debate over safety in early pregnancy; potential heartburn	Individuals with GERD or in the first trimester of pregnancy (debate)	No major interactions, but can exacerbate acid reflux

Making an informed decision

The assumption that all natural remedies are without risk is a common misconception that can lead to adverse health outcomes. The truth is that many herbal teas contain potent compounds that can be harmful when consumed in large quantities, by sensitive individuals, or in combination with certain medications. From pregnancy complications and drug interactions to allergic reactions and organ toxicity, the potential for harm is real and should not be overlooked.

Always consult a healthcare professional, such as a doctor or pharmacist, before incorporating new herbal teas into your routine, especially if you have an existing health condition or are taking medication. By taking a cautious approach, you can safely enjoy the benefits of herbal teas while avoiding potential dangers.

Conclusion

Herbal teas are not universally safe and should be approached with caution, especially for specific populations. The most significant risks include dangerous interactions with prescription medications, such as blood thinners and antidepressants. Pregnant and breastfeeding individuals should avoid most herbal teas due to insufficient safety data and the risk of complications. People with existing health conditions, including liver or kidney disease and iron deficiency, need to be particularly careful. The potential for allergic reactions to specific plants also exists. By understanding when you should not drink herbal tea and consulting a healthcare professional, you can minimize risks and make informed decisions about your nutritional diet. Prioritizing safety over the assumption of naturalness is the key to incorporating herbal teas responsibly into your lifestyle. For more information, the National Center for Complementary and Integrative Health provides resources on herbs and their interactions with medicines.

Frequently Asked Questions

Yes, many herbal teas contain potent compounds that can interact with prescription medications. For example, St. John's wort can reduce the effectiveness of birth control pills and HIV medications, while ginkgo biloba can affect blood thinners and antidepressants. Always consult a healthcare provider before combining herbal tea with medication.

Pregnant women should avoid many herbal teas due to a lack of safety research and potential risks. Herbs that may stimulate the uterus, such as pennyroyal, wormwood, and large amounts of parsley, should be avoided. Teas like chamomile and raspberry leaf also have conflicting safety data and are best discussed with a doctor.

Yes, it is possible to have an allergic reaction to herbal teas, especially if you have known allergies to specific plants. Common reactions can include hives, skin irritation, and respiratory symptoms. People with ragweed allergies, for instance, may react to chamomile tea.

Yes, certain herbal teas can be harmful to the liver and kidneys, particularly with excessive or long-term consumption. Comfrey and chaparral are two herbs known to cause liver damage. Individuals with pre-existing liver or kidney conditions should be especially cautious.

Some herbal teas, especially those that contain caffeine (though most true herbal teas are caffeine-free), can influence blood pressure. Licorice root tea can also raise blood pressure and should be avoided by those with hypertension.

Some herbal teas, due to their tannin content, can cause nausea or stomach irritation when consumed on an empty stomach. Certain teas are also acidic and may affect the stomach's acid-base balance, potentially causing discomfort.

Yes, teas, including many herbal and green teas, contain tannins that can inhibit the absorption of iron, particularly non-heme iron from plant-based foods. Individuals with low iron levels or anemia should consume these teas between meals rather than with them.