Which Supplements Surgical Teams Ask About and Why
Supplements and herbs that the ASA, NIH and surgical reviews name in connection with bleeding, anesthesia or blood pressure, what each source found, and why the surgical team decides what to do.
Content last updated . This page has not been medically reviewed.
Surgical and anesthesia teams ask about supplements because some have documented or suspected effects on bleeding, anesthesia, heart rate or blood pressure. This page lists the products that official bodies and published reviews name most often, and what each source actually found. It is information only. It does not say what you should stop, and it gives no stop dates: your surgical and anesthesia team decides, and the prescriber or pharmacist advises on prescribed medicines.
Two cautions apply to every row. First, the guidance we read speaks of "supplements" and usually does not say which plant part, extract or amount was involved, and a result for one product does not transfer to another. Second, absence from this page does not mean a product is safe. Tell your team about everything you take.
Products named for bleeding
| Supplement | What the source found | Label |
|---|---|---|
| Garlic supplements (Allium sativum) | NCCIH says garlic supplements may increase the risk of bleeding, especially important before surgery or with anticoagulants or aspirin. [1] The ASA says the same. [2] A literature review found garlic strongly associated with surgical bleeding independent of anticoagulants. [3] | Official guidance plus review; see garlic |
| Hawthorn (Crataegus, for example Crataegus monogyna) | The same review found hawthorn supplementation strongly associated with surgical bleeding independent of anticoagulants. [3] | One review; see hawthorn |
| Ginkgo (Ginkgo biloba) | NCCIH says ginkgo may increase bleeding risk in people taking anticoagulants such as warfarin. [4] The ASA says it can increase the risk of bleeding. [2] The review found bleeding risk with anticoagulants, and conflicting evidence overall. [3] | Mixed; see ginkgo |
| Vitamin E | The ASA says it can increase bleeding and cause blood pressure problems. [2] FDA says warfarin, ginkgo, aspirin and vitamin E can each thin the blood. [5] | Official guidance; see vitamin E |
| Ginger, St. John's wort, cranberry | The review found conflicting evidence on overall bleeding risk. [3] | Mixed |
| Turmeric, bilberry, chamomile, fenugreek, milk thistle, peppermint, melatonin, chondroitin-glucosamine | The review found these associated with bleeding risk in people on anticoagulants, with no evidence of bleeding independent of anticoagulants. [3] | Limited; interaction with a blood thinner |
| Fish oil, saw palmetto | The review found these not associated with bleeding. [3] | One review; do not read as "safe" for everyone |
| Ginseng | The ASA says ginseng can increase heart rate and the risk of bleeding. [2] The review found ginseng not associated with bleeding. [3] The sources do not say which kind of ginseng they mean; see ginseng types compared. | Sources disagree |
A second review of bleeding risks of herbal, homeopathic and dietary supplements, written for plastic surgeons, reported rising numbers of hematomas linked to these products. [6] A dental case report described severe bleeding after implant surgery in a patient who had taken supplements for one month. [7]
Products named for anesthesia, sedation and blood pressure
| Supplement | What the source found | Label |
|---|---|---|
| Kava (Piper methysticum) | The ASA says kava can increase the effect of anesthesia. [2] NCCIH says kava should not be combined with other sedating substances such as benzodiazepines or alcohol. [8] A review describes possible effects on blood pressure and sedation, based on mechanisms. [9] | Official guidance; mechanism-based review; see kava |
| Valerian (Valeriana officinalis) | The ASA says valerian can prolong the effects of some types of anesthesia. [2] NCCIH says valerian should not be taken with alcohol or sedatives. [10] | Official guidance |
| St. John's wort (Hypericum perforatum) | The ASA says it may prolong the effects of anesthesia. [2] NCCIH says it can weaken the effects of many medicines, including warfarin. [11] | Official guidance; see St. John's wort interactions |
| Ephedra (ma huang) | FDA has banned supplements containing ephedrine alkaloids because of serious safety risks. [12] The ASA says it can interact with some blood pressure medicine to cause dangerous rises in blood pressure or heart rate. [2] | Official guidance; banned in supplements in the US |
| Kratom | A 2026 perioperative nursing review links kratom to difficulty managing pain, unstable circulation, agitation and withdrawal in surgical patients. [13] See kratom. | Review of reports |
| Cannabinoid products | An expert consensus says patients should be asked specifically about cannabinoids because many will not volunteer them. [14] | Disclosure point only; we found no more detail in sources read |
How much weight can these rows carry?
Not as much as the tidy table suggests. The 2021 consensus statement covered 83 supplements and says guidance is often lacking. [14] Its reasoning was that without a demonstrated benefit, or with a demonstrated lack of harm, there is little downside in temporarily discontinuing an herbal supplement before surgery. [14] That is a consensus judgment, not a trial result, and it is addressed to clinicians. A 2026 narrative review is open about this: its recommendations rest largely on pharmacological reasoning, case reports and consensus rather than prospectively validated evidence. [15]"Proper evidence not found": we searched PubMed and the NIH, FDA and ASA pages listed below for a randomized trial that tested how long before surgery each supplement must be stopped, and found none.
What the sources suggest a reader can do
- Tell the surgical team, the anesthesia provider and the pharmacist about every product, in advance if possible. [16]
- Bring the bottles or a written list. [2]
- Ask the team what applies to you. FDA says providers may ask you to stop two or three weeks ahead, and NCCIH says some ask for several weeks, but this is for them to decide. [5] [16]
- Do not change prescribed medicines on your own.
Related: Supplements before surgery, How to prepare your supplement list, Supplements and blood thinners.
Frequently asked questions
Which supplement is the biggest concern before surgery?
The sources do not rank them, and we do not either. Garlic and hawthorn had the strongest link to surgical bleeding in one review. [3] Ephedra supplements are banned in the US. [12]
Do fish oil and ginseng cause bleeding?
Sources disagree on ginseng, and one review found fish oil not associated with bleeding. [3] [2] Tell your team about them anyway.
Is a supplement safe if it is not on this list?
Not necessarily. Absence of a warning is not proof of safety, and the ASA notes ingredient levels in supplements can vary. [2]
Do I need to mention cannabis or CBD products?
Yes. An expert consensus says to ask specifically about cannabinoids because many patients do not volunteer them. [14]
Can I decide my own stop date?
Ask your team. The sources describe windows of two weeks to several weeks, but they are descriptions of what clinicians may ask, and your procedure and medicines matter. [2] [5]
References
- National Center for Complementary and Integrative Health (NIH). Garlic: Usefulness and Safety. Read 2026-10-23.
- American Society of Anesthesiologists. Herbal and Dietary Supplements and Anesthesia (patient brochure, 2020). Read 2026-10-23.
- Hatfield J, Saad S, Housewright C. Dietary supplements and bleeding. Proc (Bayl Univ Med Cent) 2022 (literature review). Read 2026-10-23.
- National Center for Complementary and Integrative Health (NIH). Ginkgo: Usefulness and Safety. Read 2026-10-23.
- U.S. Food and Drug Administration. Mixing Medications and Dietary Supplements Can Endanger Your Health. Read 2026-10-23.
- Wong WW, Gabriel A, Maxwell GP, Gupta SC. Bleeding risks of herbal, homeopathic, and dietary supplements: a hidden nightmare for plastic surgeons? Aesthet Surg J 2012 (review). Read 2026-10-23.
- Grisa A, Florio S, Bellia E, et al. The Role of Dietary Supplements in Postsurgical Bleeding: An Update for the Practitioner. Compend Contin Educ Dent 2016 (case report and review). Read 2026-10-23.
- National Center for Complementary and Integrative Health (NIH). Kava. Read 2026-10-23.
- Raduege KM, Kleshinski JF, Ryckman JV, Tetzlaff JE. Anesthetic considerations of the herbal, kava. J Clin Anesth 2004 (review). Read 2026-10-23.
- National Center for Complementary and Integrative Health (NIH). Valerian. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NIH). St. John's Wort. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NIH). Ephedra. Read 2026-10-23.
- Vance BS, Miner L, Ostrowski A. Kratom Use: An Emerging Perioperative Nursing Concern. AORN J 2026. Read 2026-10-23.
- Cummings KC 3rd, Keshock M, Ganesh R, et al. Preoperative Management of Surgical Patients Using Dietary Supplements: SPAQI Consensus Statement. Mayo Clin Proc 2021. Read 2026-10-23.
- Sousa Oliveira LA, Cabette Filho NN, et al. Self-Administered Dietary Supplements, Herbal Products, and Ergogenic Aids Before Plastic Surgery: A Narrative Review. Cureus 2026. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NIH). Know the Science: Some Medication-Supplement Interactions Can Be Serious. Read 2026-10-23.