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Panax ginseng and warfarin: does ginseng change how warfarin works?

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

Ask your pharmacist or doctor before combining. Two official sources name ginseng: the warfarin label lists it among botanicals that may decrease warfarin's effect, and MedlinePlus lists it among herbal products that may interact. The label asks for more frequent INR checks when a botanical is started or stopped.1,2

Key facts

  • The warfarin label names co-enzyme Q10, St. John's wort and ginseng as botanicals that may decrease warfarin's effect.1
  • MedlinePlus lists ginseng among the nonprescription and herbal products that may interact with warfarin, and says not to start any of them without talking to your healthcare provider.2
  • NIH's liver injury database mentions a reported case of a weaker warfarin effect with ginseng.3
  • In 24 healthy people given one warfarin dose, Asian ginseng modestly raised how fast the body cleared one form of warfarin and had no direct effect on warfarin's action.4
  • The label says few well-controlled studies of botanicals with warfarin exist, and that botanical products vary in strength.1

Ask your pharmacist or doctor first

The warfarin label lists ginseng among the botanicals that may decrease warfarin's effect, and says the INR, the blood test that guides the dose, should be checked more often when starting or stopping botanicals. MedlinePlus also names ginseng among the herbal products that may interact with warfarin.1,2,3

On the medicine's label

What does the warfarin label say about ginseng?

The label has a section on botanical products and foods. It says some botanicals may decrease the effects of warfarin and gives co-enzyme Q10, St. John's wort and ginseng as examples. It also says INR monitoring should be done more often when botanicals are started or stopped.1

The label is open about its limits. Few adequate, well-controlled studies of botanicals with warfarin exist, and because botanical preparations are not standardized the amount of active ingredient can vary. That makes it hard to predict what a given ginseng product will do.1

Does ginseng make warfarin weaker or stronger?

The sources point toward weaker. The label lists ginseng among botanicals that may decrease warfarin's effect, which is the opposite direction from herbs such as garlic and ginkgo that the same label says may add to bleeding. MedlinePlus says warfarin is used to prevent and treat blood clots, so a weaker effect would mean less protection than intended. That is the reason the INR blood test matters.1,2

NIH's liver injury database, in its ginseng chapter, mentions a reported case of a weaker warfarin effect. A systematic review of ginseng's adverse effects also reported possible interactions with warfarin.3,5

A small study gave one dose of warfarin to 24 healthy people along with St. John's wort, Asian ginseng, ginkgo or ginger. Asian ginseng modestly raised the rate at which the body cleared one form of warfarin but had no direct effect on how warfarin acts. The authors said studies in people who take warfarin are needed to judge whether it matters.4

What does NIH say about ginseng and blood clotting?

Asian ginseng may worsen autoimmune conditions and interfere with blood clotting.6

NIH's complementary health center does not name warfarin on its current Asian ginseng page, so the warfarin link rests on the label and MedlinePlus. The page does say Asian ginseng might interact with certain medications and asks people who take any medicine to talk with their health care provider first.6

Which ginseng do these sources mean?

The label and MedlinePlus say ginseng without naming a species. The studies and NIH pages cited here concern Asian ginseng, Panax ginseng, which NIH says goes by common names including Korean ginseng, red ginseng and white ginseng.1,2,6

Asian ginseng, Panax ginseng, is the form most commonly used. American ginseng, Panax quinquefolius, is a separate species with similar properties.3

Siberian ginseng comes from a different genus and contains eleutherosides rather than ginsenosides. Ashwagandha, sometimes called Indian ginseng, does not belong to the ginseng family.7,8

The sources on this page do not say whether American or Siberian ginseng behave the same way with warfarin. That is not a finding either way. NIH adds that commercial ginseng products vary widely in ginsenoside content, so two products with the same name can differ.6

What to ask your pharmacist about ginseng and warfarin

  • Should my INR be checked more often if I start or stop ginseng?
  • Do any of my products contain ginseng under another name, such as Korean ginseng or red ginseng?
  • Does the species of ginseng matter for my warfarin?
  • Who should I tell at the clinic that manages my warfarin, and when?

Questions people ask

Does Panax ginseng interact with warfarin?

The warfarin label lists ginseng among botanicals that may decrease warfarin's effect, and MedlinePlus lists it among herbal products that may interact. Ask your pharmacist before combining.1,2

What about red ginseng and warfarin?

NIH says red and white ginseng are both Asian ginseng, prepared in two different ways. The label does not separate preparations, so ask your pharmacist about the product you use.1,6

What about Korean ginseng and warfarin?

NIH lists Korean ginseng as a common name for Panax ginseng, the plant the studies on this page concern. The same questions about the INR apply.6

What about Panax ginseng and blood thinners other than warfarin?

NIH says Asian ginseng may interfere with blood clotting, but the label and MedlinePlus pages on this page are about warfarin. For another blood thinner, ask your pharmacist.6

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Sources

  1. Warfarin sodium tablets: prescribing information (A-S Medication Solutions). DailyMed, U.S. National Library of Medicine. Published September 23, 2026. Opened 2026-10-07.
  2. MedlinePlus. Warfarin. U.S. National Library of Medicine. Last revised March 15, 2026. Opened 2026-10-07.
  3. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Ginseng. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases. Last updated March 14, 2018. Opened 2026-10-07.
  4. Jiang X, Blair EY, McLachlan AJ. Investigation of the effects of herbal medicines on warfarin response in healthy subjects: a population pharmacokinetic-pharmacodynamic modeling approach. J Clin Pharmacol. 2006;46(11):1370-1378. Opened 2026-10-07.
  5. Coon JT, Ernst E. Panax ginseng: a systematic review of adverse effects and drug interactions. Drug Saf. 2002;25(5):323-344. Opened 2026-10-07.
  6. National Center for Complementary and Integrative Health. Asian Ginseng. Last updated February 2025. Opened 2026-10-07.
  7. Kim HG, Cho JH, Yoo SR, et al. Antifatigue effects of Panax ginseng C.A. Meyer: a randomised, double-blind, placebo-controlled trial. PLoS One. 2013;8(4):e61271. Opened 2026-10-07.
  8. National Institutes of Health, Office of Dietary Supplements. Ashwagandha: Is it helpful for stress, anxiety, or sleep? Fact Sheet for Health Professionals. Updated May 2, 2025. Opened 2026-10-07.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.