NutriStack
Aspirin Low-Dose and Nattokinase, a caution.
Nattokinase is a fibrinolytic enzyme that directly degrades fibrin and reduces clotting factors. A documented case describes cerebellar hemorrhage in a patient with cerebral microbleeds who took aspirin plus nattokinase 400 mg/day for 7 days. The combination is particularly risky in patients with cerebral microangiopathy.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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At a glance
- Substances
- Aspirin Low-Dose and Nattokinase
- Pair type
- Caution
- Evidence (highest tier)
- Emerging
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Emerging evidence
Caution
What is happening. Nattokinase is a fibrinolytic enzyme that directly degrades fibrin and reduces clotting factors. A documented case describes cerebellar hemorrhage in a patient with cerebral microbleeds who took aspirin plus nattokinase 400 mg/day for 7 days. The combination is particularly risky in patients with cerebral microangiopathy.
Mechanism. Nattokinase directly cleaves fibrin and activates plasmin-mediated fibrinolysis, while reducing fibrinogen and factor VII/VIII. These effects add to aspirin's irreversible COX-1 inhibition of platelet thromboxane A2 production, sharply raising bleeding risk.
Recommendation. Avoid nattokinase while on aspirin, especially if you have a history of stroke, cerebral microbleeds, or uncontrolled hypertension. If you have been taking both, stop the nattokinase and call your prescriber.
Sources (2)
- Chang YY, Liu JS, Lai SL, Wu HS, Lan MY. Cerebellar hemorrhage provoked by combined use of nattokinase and aspirin in a patient with cerebral microbleeds. Intern Med. 2008;47(5):467-9. PMID 18310985
- Elahi MM, Choi CH, Konda S, Shake JG. Consequence of patient substitution of nattokinase for warfarin after aortic valve replacement with a mechanical prosthesis. Proc (Bayl Univ Med Cent). 2015;28(1):81-2. PMID 25552810
Stack Score
How this pair moves the number.
Effect on the composite score
If both Aspirin Low-Dose and Nattokinase are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
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