Anesthesia and Herbal Supplements: What Anesthesiology Sources Say

The short answer: anesthesiology sources say some herbal and dietary supplements can react with anesthesia or change blood pressure, heart rate or bleeding, and they ask you to tell your anesthesia provider about everything you take. How long to stop any product, if at all, is for your team to decide. This page separates what official bodies state from what comes from mechanism reviews and surveys.

What the American Society of Anesthesiologists says

The ASA's patient brochure says herbal supplements can cause problems during surgery, such as reacting with the anesthesia used to control pain. [1] It lists five ways supplements may add risk: prolonging the effects of anesthesia, raising bleeding risk, raising blood pressure, interfering with other medications and causing heart problems. [1]

At your pre-surgery visit, the physician anesthesiologist asks about your health and medicines, and the ASA asks you to include herbs and dietary supplements, including vitamins. [1] It suggests bringing all medication and supplement bottles, and says that in some cases the anesthesiologist may recommend stopping supplements at least two weeks before the procedure. [1] That window is a statement about what some anesthesiologists recommend, not a rule that fits every product or person.

Documented statements by product

These are official-guidance statements, not trial results for your situation. For more products and bleeding, see which supplements surgical teams ask about.

Mechanism and review findings

These come from review articles and describe what might happen, not how often it does.

• Kava. A 2004 anesthesiology review says kava may lower blood pressure by acting on sodium and calcium channels, and may increase the potency of benzodiazepines and induction anesthetics, causing excessive sedation. [5] NCCIH separately says kava should not be used with other sedating substances such as benzodiazepines or alcohol. [6] NCCIH also notes that various kava products have been linked to rare cases of liver injury. [6] See kava.
• Herbs in general. A 2002 review lists effects herbs can have in anesthesia: clotting problems, cardiovascular effects, water and electrolyte disturbances, endocrine effects, liver toxicity and prolonged effects of anesthetic agents. It advises anesthesiologists to take a history of herbal use. [7]
• Product quality. A 2018 nurse-anesthesia review says lack of FDA oversight leads to product variation in quality, purity, efficacy, harvesting and storage, and asks anesthesia providers to know about interactions and possible contaminants. [8] See product quality and contamination.
• Cytochrome P450 and other concerns. A 2026 narrative review links several self-administered products to bleeding, unstable blood pressure under anesthesia, cytochrome P450-mediated interactions and impaired wound healing. [9]
• Kratom. A 2026 perioperative nursing review links kratom to difficulty managing pain, hemodynamic instability, agitation and withdrawal symptoms in surgical patients. [10] See kratom.

Limits of the evidence

• The 2021 SPAQI consensus on 83 supplements says guidance is often lacking. [11] The 2026 review says its recommendations rest mostly on pharmacological reasoning, case reports and consensus. [9]
• Practice varies. In a survey sent in 2006 to UK anesthetic departments (233 replied), 7.3% had a perioperative herbal medicine policy, and the advice patients got was varied and generally not in line with existing guidelines. [12] That is an old survey of one country; it shows variation, not today's practice.
• "Proper evidence not found": the sources we read do not describe separate supplement rules for general anesthesia, regional anesthesia, local anesthesia or sedation. We searched PubMed and the ASA and NIH pages for this and found no such breakdown.

What to tell your anesthesia provider

• Every supplement, herb, tea and oil, plus vitamins. [1]
• Products used for sleep, anxiety or appetite suppression. The ASA names kava, valerian, St. John's wort and ephedra in its anesthesia warnings. [1]
• Cannabinoid products: expert consensus says clinicians should ask because many patients do not volunteer them. [11]
• The ASA says half of people who use herbal supplements do not tell their doctors before surgery. [1]
• If surgery is an emergency, you or a loved one should still tell the surgeon and anesthesia provider what you take. [13]

Never stop a prescribed medicine on your own; ask the prescriber or pharmacist. See Supplements before surgery, Sedatives, sleep medicines and alcohol and adaptogens before surgery and anesthesia. If someone has trouble breathing after a procedure, call 911.