II. History

  1. Used in ancient medicine as far back as 5000 years ago

III. Mechanism

  1. Active ingredient: Thiosulfinates (e.g. Allicin)
  2. Alliin converted to Allicin by alliinase enzyme
    1. Alliinase released when Garlic crushed or chopped
    2. Alliinase deactivated by heat and Stomach acid
    3. Therefore Allicin most active in raw, fresh form

IV. Efficacy: Well supported benefits

  1. Moderate lipid lowering effect (initial)
    1. Total Cholesterol may be reduced 4-6% initially
    2. Longterm benefits are unclear
    3. Stevinson (2000) Ann Intern Med 133:240-9 [PubMed]
  2. Antihypertensive effect
    1. Lowers SBP up to 7 mmHg
    2. Lowers DBP up to 5 mmHg
    3. Ackermann (2001) Arch Intern Med 161:813-24 [PubMed]

V. Efficacy: Variable benefits

  1. Decreased risk of thrombosis and atherosclerosis
  2. Decreased Stomach Cancer and Colon Cancer risk
  3. Decreased infection risk

VI. Adverse Effects

  1. Halitosis and altered body odor
  2. Gastrointestinal upset
  3. Flatulence

VII. Precautions

  1. May prolong Bleeding Time
  2. Stop 7-10 days before surgery

VIII. Dosing

  1. Raw Garlic: 4 grams (1-2 cloves) daily
  2. Dried powder (enteric coated) 300 mg bid to tid
  3. Aged Garlic extract 7.2 grams daily

IX. Drug Interactions

  1. May decrease drug levels of agents transported by P-Glycoprotein

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Related Studies

Ontology: allicin (C0051200)

Definition (NCI_CRCH) An allyl-S-compound with the structure C=CCS(=O)SCC=C.
Concepts Pharmacologic Substance (T121)
MSH C006452
English allicin, thio-2-propene-1-sulfinic acid S-allyl ester, Allicin, Diallyldisulfid-S-oxid, 3-prop-2-enylsulfinylsulfanylprop-1-ene, 2-propene-1-sulfinothioic acid S-2-propenyl ester, ALLICIN

Ontology: Garlic preparation (C0885057)

Definition (NCI) The alcoholic extract of the bulb or whole garlic plant Allium sativum (Liliaceae) with potential antineoplastic activity. The garlic plant has long been considered a beneficial plant for health and has been used as an antihelmintic, a rubefacient, an anti-infective, and an antihypertensive. Fresh or aged, garlic extracts contain compounds such as diallyl and allyl propyl disulfides with potent antioxidant, cholesterol-lowering properties; regular ingestion may be preventative for atherosclerosis and cardiovascular diseases. (NCI04)
Definition (PDQ) A bulbous herb isolated from the plant Allium sativum with potential antineoplastic activity. Garlic contains a number of different organosulfur compounds, some of which have displayed antineoplastic activity. Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=357490&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=357490&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C38706" NCI Thesaurus)
Concepts Organic Chemical (T109) , Pharmacologic Substance (T121)
SnomedCT 329509009, 411618001
English Garlic Extract, Allium sativum Extract, ajo, Garlic, garlic extract, garlic in a drug form, garlic preparation, garlic, herbal medicines garlic, herbal medicines garlic (medication), Garlic preparation, Garlic product, Garlic product (product), Allium sativum, Garlic product (substance), Allium sativum extract (product), Allium sativum extract
Spanish ajo, ajo, producto (producto), ajo (producto), ajo, producto, extracto de Allium sativum (producto), extracto de Allium sativum