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SupplementScience

Garlic Side Effects & Safety

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Generally Safe

Potential Side Effects

  • Garlic breath and body odor (minimized with aged garlic extract)
  • GI irritation, heartburn, and nausea, particularly with raw garlic on an empty stomach
  • Allergic reactions (rare) — contact dermatitis or GI hypersensitivity
  • Increased bleeding risk in some individuals due to antiplatelet effects

Drug & Supplement Interactions

  • Anticoagulants (warfarin, aspirin) — garlic has antiplatelet activity; may increase bleeding risk; monitor INR
  • HIV protease inhibitors (saquinavir) — garlic may reduce blood levels of certain antiretroviral drugs
  • CYP2E1 substrates — garlic may induce this enzyme; potential interaction with acetaminophen and other medications
  • Pre-surgery — discontinue garlic supplements 7-10 days before surgery due to bleeding risk

Maximum Dose

Do not exceed: No established upper limit for dietary garlic; AGE studies have used up to 2.56g/day safely

Full Garlic Guide

References

  1. (). Preventing the common cold with a garlic supplement: a double-blind, placebo-controlled survey. Advances in Therapy. DOI
  2. (). Supplementation with aged garlic extract improves both NK and gamma-delta T cell function and reduces the severity of cold and flu symptoms. Clinical Nutrition. DOI