Garlic bulbs are extracted and made into tablet form; the major active ingredient is allicin, an amino acid by-product.

Claims

Garlic is said to have favorable effects on several cardiac risk factors, including reduction of BP and serum lipid and glucose levels; garlic inhibits platelets in vitro. Garlic is also said to protect against laryngeal, gastric, colorectal, and endometrial cancer and adenomatous colorectal polyps. Scientific evidence shows limited to no protection against cancer. Garlic consumed in high doses has general antimicrobial effects.

Adverse effects

Breath and body smell and nausea may occur; high doses may cause burning in the mouth, esophagus, and stomach. Theoretically, garlic is contraindicated in patients who have bleeding diatheses or who take antihypertensives, antiplatelet drugs, or warfarin. Garlic can reduce serum saquinavir levels.

Last full review/revision May 2009 by Ara DerMarderosian, PhD