NSTK · 01.2026Independent supplement reference
NutriStack
Edition 1.0Updated August 1, 2026

Supplement × Prescription·Evidence index

Garlic Extract and Warfarin: what the published research says

PubMed indexes 4 records that name Garlic Extract and Warfarin together, either in the title or in an interaction, co-administration, or pharmacokinetic context. Each one is listed below with its study design and, where the abstract states one, the authors’ own conclusion, quoted and linked. This page reports that literature. It does not tell you whether to combine them.

Read this first

An evidence index, not guidance.

Every statement below is attributed to a named, dated, linked source.

This page lists published research relevant to Garlic Extract and Warfarin. It deliberately does not state whether the combination is safe, whether it interacts, in which direction, at what dose, or how far apart to take them.

The research

4 studies naming Garlic Extract and Warfarin.

Strongest relevance first: papers naming both substances in the title, then human trials and systematic reviews.

A systematic review of the pharmacokinetic and pharmacodynamic interactions of herbal medicine with warfarin.

PloS one · 2017 · PMID 28797065

Systematic ReviewHuman subjects

“It was difficult to determine whether ten herbal medicines had significant effects on the PK-PD parameters of warfarin. Low quality of evidence, different compounds within and different compositions of the herbs, and methodological limitations of the crossover study, which is a clinical study in which subjects receive a sequence of different interventions, made it difficult to form conclusions.”

Choi et al. · Authors' conclusion

Names Garlic Extract and Warfarin together in an interaction, co-administration, or pharmacokinetic context.

Clinical evidence of herb-drug interactions: a systematic review by the natural standard research collaboration.

Current drug metabolism · 2008 · PMID 19075623

Systematic ReviewHuman subjects

“As herbal products (and dietary supplements in general) continue to grow in popularity, patients and health care providers should be vigilant of potential herb-drug interactions.”

Ulbricht et al. · Authors' conclusion

Names Garlic Extract and Warfarin together in an interaction, co-administration, or pharmacokinetic context.

Limitations

What this evidence cannot tell you.

Search-based evidence indexes have real limits, and it is worth being explicit about them:

NutriStack

Track what you actually take.

NutriStack is a free iPhone app for organising a supplement routine: what you take, when, and what the published record says about it. Its exploratory interaction checker covers Garlic Extract, Warfarin, and several hundred other substances.

The checker is a research and organisation tool, not a clinical decision aid, and its per-pair assessments are excluded from search until they pass claim-level review.

NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.