Omnia Sana · Plant Monograph
Garlic
Allium sativum
This monograph compiles 1 documented constituent, 6 pharmacological actions, 10 traditional / indicated uses, supported by 12 cited sources, drawn directly from the Omnia Sana plant database.
Key Constituents
Allicin (diallyl thiosulfinate), formed enzymatically when raw garlic is crushed, together with ajoene and the aged-garlic compound S-allyl-cysteine, are the principal bioactives behind garlic's antimicrobial and cardiovascular effects — acting partly by raising nitric oxide and by targeting microbial thiol-containing enzymes.
Pharmacological Actions
Traditional & Indicated Uses
inferred from anti-inflammatory action
more plants for arthritis / joint pain →detailed sources →inferred from antidiabetic action
more plants for blood sugar / diabetes support →detailed sources →inferred from immunomodulator action
more plants for cold & flu →detailed sources →inferred from antifungal action
more plants for infection (general) →detailed sources →inferred from anti-inflammatory action
more plants for inflammation (general) →detailed sources →inferred from antidiabetic action
more plants for metabolic support →detailed sources →inferred from anti-inflammatory action
more plants for skin irritation →detailed sources →inferred from antimicrobial action
more plants for wounds →detailed sources →Safety, Cautions & Contraindications
Garlic is generally very safe at culinary and supplemental doses for most healthy adults. Raw garlic contains allicin (formed when crushed) at concentrations that can irritate the gastrointestinal tract — nausea, heartburn, flatulence, and diarrhoea are the most common side effects, especially with large amounts of raw garlic on an empty stomach. Garlic may inhibit platelet aggregation and enhance anticoagulant effects of warfarin — use caution with blood-thinning medications, especially before surgery (stop 7–10 days prior). May lower blood pressure and blood sugar — caution when combined with antihypertensive or antidiabetic medications. Topical raw garlic can cause chemical burns (contact dermatitis) and should not be applied undiluted to skin for prolonged periods. Odour (from allicin metabolites) affects breath and perspiration. Pregnancy: culinary amounts safe; avoid medicinal-dose supplements due to blood-thinning risk (National Center for Complementary and Integrative Health, 2021).
Duke (2002) rates garlic as +++ with exceptional clinical evidence (score 3) for antiseptic activity, and score 2 for anti-aggregant (antiplatelet), antiatherosclerotic, antiatherogenic, antibacterial, and antimycotic effects — among the most clinically validated herbal medicines. Commission E approves garlic for arteriosclerosis prevention and elevated blood lipids. Dose: 4 g (1 clove) fresh garlic daily, or 300 mg standardized dry powder extract (1.3% allicin) three times daily. Important interaction: garlic significantly potentiates anticoagulant medications (warfarin, aspirin) due to its anti-aggregant effects; use with caution in patients on blood thinners (Duke, 2002).
References & Sources
- Sleiman, C., Daou, R.M., Al Hazzouri, A., Hamdan, Z., Ghadieh, H.E., Harbieh, B. and Romani, M (2024) 'Garlic and Hypertension: Efficacy, Mechanism of Action, and Clinical Implications', Nutrients, 16(17). doi:10.3390/nu16172895 Preclinical
https://doi.org/10.3390/nu16172895 - Serrano, J.C.E., Castro-Boque, E., Garcia-Carrasco, A., Moran-Valero, M.I., Gonzalez-Hedstrom, D., Bermudez-Lopez, M. and others (2023) 'Antihypertensive Effects of an Optimized Aged Garlic Extract in Subjects with Grade I Hypertension and Antihypertensive Drug Therapy: A Randomized, Triple-Blind Controlled Trial', Nutrients, 15(17). doi:10.3390/nu15173691 Randomized trial
https://doi.org/10.3390/nu15173691 - Choo, S., Chin, V.K., Wong, E.H., Madhavan, P., Tay, S.T., Yong, P.V.C. and Chong, P.P (2020) 'Review: antimicrobial properties of allicin used alone or in combination with other medications', Folia Microbiologica, 65(3), pp. 451--465. doi:10.1007/s12223-020-00786-5 Preclinical
https://doi.org/10.1007/s12223-020-00786-5 - Josling, P (2001) 'Preventing the common cold with a garlic supplement: a double-blind, placebo-controlled survey', 18(4), pp. 189--193. doi:10.1007/BF02850113 Randomized trial
https://doi.org/10.1007/BF02850113 - Mikaili, P., Maadirad, S., Moloudizargari, M., Aghajanshakeri, S. and Sarahroodi, S (2013) 'Therapeutic uses and pharmacological properties of garlic, shallot, and their biologically active compounds', 16(10), pp. 1031--1048. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC3874089/ Traditional / reference
https://pmc.ncbi.nlm.nih.gov/articles/PMC3874089/ - National Center for Complementary and Integrative Health (2021) 'Garlic'. Available at: https://www.nccih.nih.gov/health/garlic Traditional / reference
https://www.nccih.nih.gov/health/garlic - Ried, K (2016) 'Garlic lowers blood pressure in hypertensive individuals, regulates serum cholesterol, and stimulates immunity: an updated meta-analysis and review', 146(2), pp. 389S--396S. doi:10.3945/jn.114.202192 Meta-analysis / review
https://doi.org/10.3945/jn.114.202192 - Royal Botanic Gardens, Kew (n.d.) 'Allium sativum L'. Available at: https://powo.science.kew.org/taxon/urn:lsid:http://ipni.org:names:530118-1 Traditional / reference
https://powo.science.kew.org/taxon/urn:lsid:http://ipni.org:names:530118-1 - World Cancer Research Fund/American Institute for Cancer Research (2018) 'Diet, Nutrition, Physical Activity and Cancer: a Global Perspective (Continuous Update Project Expert Report)'. Available at: https://www.wcrf.org/dietandcancer Traditional / reference
https://www.wcrf.org/dietandcancer - Imaizumi, V.M., Laurindo, L.F., Manzan, B., Guiguer, E.L., Oshiiwa, M., Otoboni, A.M.M.B. and others (2022) 'Garlic: A systematic review of the effects on cardiovascular diseases', Critical Reviews in Food Science and Nutrition, 63(24), pp. 6797--6819. doi:10.1080/10408398.2022.2043821 Meta-analysis / review
https://doi.org/10.1080/10408398.2022.2043821 - Reiter, J., Levina, N., van der Linden, M., Gruhlke, M., Martin, C. and Slusarenko, A.J (2017) 'Diallylthiosulfinate (Allicin), a Volatile Antimicrobial from Garlic (Allium sativum), Kills Human Lung Pathogenic Bacteria, Including MDR Strains, as a Vapor', Molecules, 22(10). doi:10.3390/molecules22101711 Preclinical
https://doi.org/10.3390/molecules22101711 - Ried, K (2016) 'Garlic Lowers Blood Pressure in Hypertensive Individuals, Regulates Serum Cholesterol, and Stimulates Immunity: An Updated Meta-analysis and Review', Journal of Nutrition, 146(2), pp. 389S--396S. doi:10.3945/jn.114.202192 Meta-analysis / review
https://doi.org/10.3945/jn.114.202192
Generated June 22, 2026 from omniasana.bio