Drug Interaction Report

Skullcap and Aspirin: Interaction Details

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

AI-assisted, pharmacist-reviewed · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Aspirin

Acuprin® Anacin Aspirin Regimen Anacin® Aspirin Regimen Ascriptin® Aspergum Aspergum® Aspi-Cor Aspidrox®
+

Skullcap

No brand names on record
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Jul 11, 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 20 documented Skullcap interactions, 16 are rated moderate — including this one.
Onset
delayed
Evidence
theoretical
Severity
Moderate

What happens

Increased risk of bleeding

Interaction Deep Dive

Theoretically, if skullcap is taken with antiplatelet agents, excessive bleeding may occur. Flavonoid components of skullcap exhibited anti-platelet aggregation activity in rats, with some constituents having activity equal to or greater than that of aspirin1. Caution is advised.

Why it happens (mechanism)

Inhibition of platelet aggregation and the conversion of fibrinogen to fibrin by skullcap

Literature reports

1 report — tap to read

a) Flavonoids isolated from Scutellariae radix (skullcap) inhibited platelet aggregation induced by various substances in rats. Aspirin 1 millimole (mmol) inhibited collagen-induced platelet aggregation by 21.6%, whereas the same concentration of flavonoids baicalein, baicalin, wogonin, wogonin-7-O-D-glucuronide, oroxylin A, skullcapflavone II, and chrysin inhibited platelet aggregation by 23.3%, 12.4%, 24.7%, 8.9%, 43.8%, 32.5%, and 23.4%, respectively. Arachidonic acid induced platelet aggregation was inhibited by aspirin 1 mmol by 30.4%; whereas 1 mmol of baicalein, baicalin, and wogonin inhibited platelet aggregation by 47.7%, 31.3%, and 45.5%, respectively. Baicalein and baicalin inhibited the thrombin-induced conversion of fibrinogen to fibrin 1.

Common questions

Can I take Skullcap and Aspirin together?

Increased risk of bleeding Always confirm with your pharmacist or prescriber before making any change.

How serious is the Skullcap and Aspirin 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 "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

Questions for your pharmacist

  • Does my dose of Skullcap or Aspirin 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 (1)

  1. Kubo M, Matsuda H, Tani T, et al: Studies on Scutellariae radix. XII. Anti-thrombic actions of various flavonoids from Scutellariae radix. Chem Pharm Bull 1985; 33:2411-2415. DOI
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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.