That nightly cup of tea may feel like a harmless ritual — but if you’re heading into surgery, it can quietly become a problem. Certain teas contain active plant compounds that may increase bleeding risk, interfere with anesthesia, or push your blood pressure and heart rhythm in the wrong direction at the worst possible time. And because they’re “natural,” many people don’t even think to mention them.
Teas to avoid before surgery (and why):
- Ginseng tea — Can interfere with blood clotting and may affect blood sugar, which matters when you’re fasting.
- Ginger tea — Popular for nausea, but may increase bleeding risk by disrupting normal clotting.
- Ginkgo tea — Often used for memory and circulation, but can raise bleeding risk and interact with blood thinners.
- Turmeric tea — Anti-inflammatory reputation, but may increase bleeding risk and interfere with how the liver processes drugs used during anesthesia.
- Kava tea — Known for calming effects, but can dangerously amplify sedation and interact with anesthesia medications.
- St. John’s wort tea — Often used for mood, but is notorious for altering drug metabolism and potentially changing how anesthesia and other meds work.
- Licorice root tea — Can raise blood pressure and lower potassium, which may strain the cardiovascular system before surgery.
- Ma huang (ephedra) tea — A serious red flag: linked to dangerous cardiovascular effects and banned in U.S. supplements, but still found in some products.
- Yerba mate — Stimulating and caffeinated, which can affect heart rate and blood pressure and complicate surgical prep.
- Valerian tea — A sleep tea that acts on calming brain receptors, and can interact with sedatives or cause withdrawal-like effects if stopped abruptly.
The key takeaway: Tea isn’t always “just tea.” If surgery is coming up, treat herbal teas like a real medical variable — because they can act like drugs inside the body. The smartest move is to tell your surgical team exactly what you’ve been drinking, even if it seems minor, so you don’t walk into the operating room with a hidden risk in your mug.
SOURCE:
Very Well Health, January 30, 2026