Educational reference, not medical advice. Talk to a clinician before changing what you take.Read more.

Remedy · herb

Garlic

Also: Allium sativum

A kitchen bulb with modest blood-pressure-lowering evidence.

Active compounds Allicin

Evidence by condition

Each grade reflects the research for Garlic and that condition specifically.

B
High blood pressure
Modestly lowers blood pressure in people with hypertension (a few mmHg); trials are small and varied.
2 citation s
- Garlic for hypertension: A systematic review and meta-analysis of randomized controlled trials
  Meta-analysis 2015 · Phytomedicine · PMID 25837272 · DOI 10.1016/j.phymed.2014.12.013
- Complementary Health Approaches for Hypertension: What the Science Says
  NCCIH · accessed 2026-06-21
—
Common cold
Cochrane found only a single eligible trial; despite a striking result (24 vs 65 colds), the evidence is insufficient to recommend garlic for preventing colds.
1 citation
- Garlic for the common cold
  Systematic review 2014 · n=146 · Cochrane Database of Systematic Reviews · PMID 25386977 · DOI 10.1002/14651858.CD006206.pub4

What researchers studied

These describe how the remedy was used in studies — not a dose or a recommendation.

Form studied: aged garlic extract or standardized garlic powder
Amounts in trials: ~600–1,200 mg/day of extract in trials

Safety

Likely safe in pregnancy

Interactions: anticoagulant/antiplatelet drugs
some HIV drugs (saquinavir)
Side effects: breath/body odour
GI upset

Safety data is not exhaustive. Always check with a clinician or pharmacist before combining remedies or medications.

Known interactions

Warfarin (moderate)
Garlic has antiplatelet activity that can add to warfarin's effect and increase bleeding risk.

Tradition vs. evidence

Traditional use is context, not proof. Here is what older systems claim, and how modern research treats it.

Western herbalismEvidence aligns
Long used for circulation and "the blood".