What Not to Mix Chamomile With? Understanding Drug and Herb Interactions

October 7, 2025 •

4 min read

Did you know that despite its gentle reputation, chamomile has potent compounds that can interact with certain medications and other herbs? Understanding what not to mix chamomile with is crucial for safe consumption, especially for individuals with underlying health conditions or those undergoing surgical procedures.

Quick Summary

Chamomile's interaction with specific medications and other herbs can cause adverse effects or reduce drug efficacy. Avoid combining with blood thinners, sedatives, or plants in the daisy family to ensure safety and prevent health risks.

Key Points

Blood Thinners: Avoid mixing chamomile with anticoagulants like warfarin or antiplatelet drugs such as aspirin, as this increases the risk of bleeding.
Sedatives: The sedative effect of chamomile can be amplified by alcohol, benzodiazepines, and other sleep aids, leading to excessive drowsiness.
Allergy Risk: If you are allergic to plants in the daisy family (e.g., ragweed, chrysanthemums), you may also have an allergic reaction to chamomile.
Pregnancy & Breastfeeding: Due to insufficient research and potential uterine-stimulating effects, healthcare providers typically advise against using chamomile during pregnancy and breastfeeding.
Pre-Surgery Caution: Stop using chamomile at least two weeks before any scheduled surgery to prevent increased bleeding and potential interference with anesthesia.
Liver Metabolism: Chamomile can affect the metabolism of certain drugs processed by the liver (CYP450), potentially altering their effectiveness.
Herbal Combinations: Do not combine chamomile with other sedating herbs like valerian or blood-thinning herbs such as ginkgo biloba, which can create additive effects.

Unpacking Chamomile's Potent Compounds

For centuries, chamomile has been celebrated for its calming and anti-inflammatory properties, often enjoyed as a soothing tea. However, its medicinal effects stem from active compounds, primarily flavonoids like apigenin and coumarins, which can interact with pharmaceuticals and other supplements. Understanding the biochemical basis of these interactions is key to safe usage. For example, the presence of coumarins gives chamomile mild blood-thinning properties, which is the primary reason for caution with anticoagulant medications.

Major Medication Interactions to Avoid with Chamomile

Blood Thinners and Antiplatelet Drugs

One of the most significant concerns with chamomile is its interaction with blood-thinning and antiplatelet medications. Because of its coumarin content, high or prolonged consumption of chamomile can increase the risk of bleeding when taken alongside these drugs.

Warfarin (Coumadin): Chamomile can amplify warfarin's effects, leading to an increased risk of severe bleeding.
Aspirin and NSAIDs: Combining chamomile with antiplatelet drugs and nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen can elevate the risk of bleeding.
Clopidogrel (Plavix): This antiplatelet drug can have its effects strengthened by chamomile, posing a bleeding risk.

Sedatives and Central Nervous System Depressants

Chamomile contains apigenin, a compound that can produce mild sedative effects by binding to benzodiazepine receptors in the brain. This can cause excessive drowsiness when combined with other central nervous system (CNS) depressants.

Alcohol: Mixing chamomile with alcohol can heighten sedative effects, causing increased drowsiness and impairment.
Benzodiazepines: Drugs like diazepam (Valium) or alprazolam (Xanax) can have their sedative properties amplified by chamomile.
Other Insomnia Medications: Over-the-counter or prescription sleep aids should not be combined with chamomile without medical supervision due to the risk of excessive sedation.

Medications Processed by the Liver (CYP450 Substrates)

Chamomile may inhibit certain cytochrome P450 (CYP450) enzymes in the liver, which are responsible for metabolizing many drugs. This can affect the concentration of certain medications in the body, potentially increasing or decreasing their effects.

Cyclosporine: Reports exist of increased serum cyclosporine levels when taken with chamomile, which is a concern for organ transplant recipients.
Tamoxifen and Oral Contraceptives: Chamomile may interfere with estrogen-containing drugs and therapies, possibly altering their effectiveness.

Hormonal and Allergy Concerns

Preliminary studies suggest chamomile might have some estrogenic effects, which could be problematic for those with hormone-sensitive conditions like certain cancers. Additionally, individuals with known allergies to plants in the daisy or Asteraceae family should be cautious.

Herbal Supplements to Avoid Mixing with Chamomile

Some herbal remedies share or amplify chamomile's effects, and combining them can increase the risk of side effects. Avoid mixing chamomile with these supplements without consulting a healthcare provider:

Valerian: Both herbs are used for sleep and relaxation. Combining them increases the risk of excessive drowsiness and sedation.
St. John's Wort: While often used for mood, St. John's Wort can interact with numerous drugs and shares some sedative properties with chamomile.
Ginkgo Biloba and Garlic: These are known for their blood-thinning properties and, like chamomile, can increase the risk of bleeding when combined.

Special Considerations: Pregnancy, Surgery, and Allergies

Pregnancy and Breastfeeding

Due to insufficient research and some conflicting evidence, the use of chamomile during pregnancy and breastfeeding is generally discouraged by healthcare providers. Concerns include the potential for uterine stimulation, which may increase the risk of miscarriage or premature labor, especially with concentrated or high doses.

Surgical Procedures

Because of its mild blood-thinning effects and potential interaction with sedatives, it is recommended to stop taking chamomile at least two weeks before any scheduled surgery. This helps prevent complications with bleeding and anesthesia.

Allergies

People with allergies to plants in the Compositae/Asteraceae family, which includes ragweed, chrysanthemums, and daisies, are at a higher risk of an allergic reaction to chamomile. Reactions can range from mild skin irritation to severe anaphylaxis.

Comparison Table: Chamomile Interactions


Category	Affected Medication/Supplement	Nature of Interaction	Potential Effect	References
Anticoagulants	Warfarin (Coumadin)	Increases blood-thinning effects	Higher risk of bleeding
Antiplatelets/NSAIDs	Aspirin, Ibuprofen, Naproxen	Increases anti-clotting effects	Elevated bleeding risk
Sedatives	Benzodiazepines, Alcohol	Enhances CNS depressant effects	Excessive drowsiness, sedation
Liver-Metabolized Drugs	Cyclosporine, some Antidepressants	Inhibits liver enzymes (CYP450)	Altered drug levels in blood
Hormone-Sensitive Drugs	Tamoxifen, Oral Contraceptives	May interfere with hormone effects	Altered drug efficacy
Herbal Sedatives	Valerian, St. John's Wort	Additive sedative properties	Increased drowsiness, impairment

Conclusion

While generally safe and beneficial for most people when consumed in moderation as a tea, chamomile is not a universally benign herb. Its active compounds have pharmacological properties that can lead to significant interactions with medications, other herbal supplements, and specific health conditions. The most critical interactions involve blood thinners, sedatives, and medications processed by the liver, which can lead to serious health risks. Additionally, pregnant women, those scheduled for surgery, and individuals with daisy family allergies should exercise particular caution. Always consult a healthcare provider before combining chamomile with any medication or supplement to ensure it is safe for your specific situation. For more information, you can visit the National Center for Complementary and Integrative Health (NCCIH) website.

This article is for informational purposes only and does not constitute medical advice.

Frequently Asked Questions

No, you should not mix chamomile tea with blood-thinning medications like warfarin, aspirin, or clopidogrel. Chamomile contains coumarins, which have mild blood-thinning effects that can increase your risk of bleeding.

No, it is not safe to combine chamomile with alcohol. Chamomile has sedative properties that can be enhanced by alcohol, leading to excessive drowsiness, impaired coordination, and increased central nervous system depression.

Yes, individuals with allergies to plants in the Compositae/Asteraceae family, which includes ragweed, daisies, and chrysanthemums, have a higher risk of an allergic reaction to chamomile.

The use of chamomile during pregnancy is not recommended. Some studies suggest that concentrated doses can stimulate uterine contractions, and there is a lack of safety data to support its use during this period.

Due to its potential to increase bleeding risk and interact with anesthesia, you should stop taking chamomile at least two weeks before any scheduled surgical procedure.

Chamomile can inhibit certain liver enzymes (CYP450) responsible for drug metabolism. This could alter the effects of medications processed by these enzymes, such as cyclosporine. Always consult your doctor if you take any liver-metabolized medications.

You should avoid combining chamomile with other sedating herbs like valerian and St. John's Wort. It's also wise to avoid other herbs that have blood-thinning properties, such as ginkgo biloba and garlic.