Drug Interaction Report

Clopidogrel and Garlic: Interaction Details

A pharmacist-reviewed analysis of the Clopidogrel and Garlic interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Clopidogrel

Plavix Plavix®
+

Garlic

No brand names on record
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Moderate
Can be significant — usually manageable with monitoring.
How we grade severity & evidence

Severity levels

  • Contraindicated: These should generally not be used together.
  • Major: Potentially serious — often needs a change or close monitoring.
  • Moderate: Can be significant — usually manageable with monitoring.
  • Minor: Usually limited clinical impact.

Evidence grades

  • Established: Well documented — supported by controlled studies or strong clinical data.
  • Probable: Good supporting evidence, though not definitively proven.
  • Suspected: Some evidence suggests this interaction, but it is not well established.
  • Possible: Limited or conflicting evidence; the interaction may occur.
  • Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Of 359 documented Clopidogrel interactions, 115 are rated moderate — including this one.
Onset
delayed
Evidence
established
Severity
Moderate

What happens

Increased risk of bleeding and reduced clopidogrel active metabolite exposure

Interaction Deep Dive

Concomitant use of clopidogrel with CYP2C19 inhibitors, such as garlic may cause reduced exposure of the active metabolite of clopidogrel and a reduction in platelet inhibition1. Additionally, coadministration of garlic with medications that inhibit platelet aggregation, such as clopidogrel, may increase bleeding. Inhibition of platelet aggregation by garlic may be irreversible. Normal hemostasis occurs 7 days after discontinuation of garlic 2. The ability of garlic to affect platelet aggregation depends on the product preparation, with different products containing different active constituents 11.

Why it happens (mechanism)

Additive antiplatelet effects; increased fibrinolysis; inhibition of CYP2C19-mediated metabolism of clopidogrel

Literature reports

3 reports — tap to read

a) The antiplatelet effect of garlic may add to the effect of other antiplatelet agents, increasing the risk for bleeding complications 3. Garlic has been shown to inhibit platelet aggregation when taken orally 4567.

b) Epidural hematoma and other bleeding consequences have been described in case reports when patients consumed garlic without concomitant medications known to affect blood coagulation 8910. Given orally to humans, garlic increased fibrinolytic activity possibly through activated plasminogen 7.

c) The ability of garlic to affect platelet aggregation depends on the product preparation, with different products containing different active constituents 11.

Common questions

Can I take Clopidogrel and Garlic together?

Increased risk of bleeding and reduced clopidogrel active metabolite exposure Always confirm with your pharmacist or prescriber before making any change.

How serious is the Clopidogrel and Garlic interaction?

It is rated moderate. Can be significant — usually manageable with monitoring.

How quickly could this interaction happen?

The documented onset is "delayed". Effects tend to build up gradually over days to weeks.

How strong is the evidence for this interaction?

The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.

Questions for your pharmacist

  • Does my dose of Clopidogrel or Garlic need adjusting while I take them together?
  • What symptoms should prompt me to call you or my prescriber right away?
  • Does the timing of my doses matter for this combination?
  • Is there anything you'd monitor while I'm on both?

References (11)

  1. Product Information: PLAVIX(R) oral tablets, clopidogrel bisulfate oral tablets. sanofi-aventis US LLC (per FDA), Bridgewater, NJ, 2022. DailyMed
  2. Kopp SL, Vandermeulen E, McBane RD, et al: Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: American Society of Regional Anesthesia and Pain Medicine evidence-based guidelines (fifth edition). Reg Anesth Pain Med 2025; Epub:Epub.
  3. Sunter W: Warfarin and garlic. Pharm J 1991; 246:722.
  4. Kiesewetter H, Jung F, Jung EM, et al: Effects of garlic coated tablets in peripheral arterial occlusive disease. Clin Invest 1993; 71:383-386. PubMed
  5. Kiesewetter H, Jung F, Jung EM, et al: Effect of garlic on platelet aggregation in patients with increased risk of juvenile ischemia attack. Eur J Clin Pharmacol 1993a; 45:333-336.
  6. Legnani C, Frascaro M, Gauzzaloca G, et al: Effects of a dried garlic preparation on fibrinolysis and platelet aggregation in healthy subjects. Arzneimittelforschung 1993; 43(2):119-122.
  7. Harenberg J, Giese C, & Zimmermann R: Effect of dried garlic on blood coagulation, fibrinolysis, platelet aggregation and serum cholesterol levels in patients with hyperlipoproteinemia. Atheroscler 1988; 74(3):247-249. PubMed
  8. Burnham BE: Garlic as a possible risk for postoperative bleeding. Plast Reconst Surg 1995; 95:213. DOI
  9. German K, Kumar U, & Blackford HN: Garlic and the risk of TURP bleeding. Br J Urol 1995; 76:518. PubMed
  10. Rose KD, Croissant PD, Parliament CF, et al: Spontaneous spinal epidural hematoma with associated platelet dysfunction from excessive garlic ingestion: a case report. Neurosurg 1990; 26:880-882. DOI
  11. Lawson LD, Ransom DK, Hughes BG, et al: Inhibition of whole blood platelet-aggregation by compounds in garlic clove extracts and commercial garlic products. Thromb Res 1992; 65:141-156. PubMed
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Clopidogrel

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Beyond drug–drug

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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.