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Garlic
Caution🐾Knoblauch · (Allium sativum)
Amaryllis family (Amaryllidaceae)
Description
The bulb of this amaryllis-family plant, made up of individual cloves, develops its characteristic smell only when crushed or cut, as the odourless compound alliin is enzymatically converted into sulphurous allicin. Harvested in summer, the bulb also contains ajoene, diallyl sulphides, and a notably high share — 11 to 15 percent — of inulin-type fructans. The EMA recognises standardised garlic as 'well-established use' for preventing atherosclerotic vascular changes and as supportive treatment for slightly elevated blood lipids and mild hypertension; low-odour, enteric-coated powder preparations release allicin only in the small intestine. In the kitchen, garlic is a daily digestion-supporting spice, and folk medicine also uses it for early respiratory infections. WARNING: high doses can cause gastrointestinal complaints, raw cloves on skin can cause chemical burns, and caution is advised with bleeding tendency or before surgery due to possible anticoagulant effects.
Critical drug interactions with:
Antikoagulanzien und Thrombozytenaggregationshemmer (Warfarin, Phenprocoumon, DOAKs, ASS, Clopidogrel) · HIV-Proteaseinhibitoren (Saquinavir, Ritonavir, Darunavir) · Ciclosporin
Prevention of atherosclerotic vascular changes; supportive use in slightly elevated blood lipids and mild hypertension.
Preparation & dosage
Support in atherosclerosis prevention and mild arterial hypertension; traditional use for promoting circulation.
Preparation & dosage
Low-odour standardised powder preparations (enteric-coated) for lipid and blood-pressure lowering in slightly elevated values; allicin release in the small intestine.
Preparation & dosage
Daily culinary use as a digestion-promoting and circulation-supporting spice; preventive contribution to cardiovascular health.
Preparation & dosage
Folk-medicinal use for early respiratory infections and head colds; volatile sulphur compounds are said to have mucolytic and antimicrobial effects.
Preparation & dosage
Traditional folk use for warts and superficial fungal infections; local antimicrobial action by allicin.
Preparation & dosage
High doses may cause gastrointestinal complaints (heartburn, flatulence, nausea), mouth and body odour and rarely allergic reactions. Raw cloves directly on skin can cause chemical burns. Caution with bleeding tendency, before surgery or dental procedures and with concurrent anticoagulation. ASPCA classification (accessed 2026-08-10): toxic to dogs and cats.
⏱ Max continuous use: 12 weeks
Usual culinary amounts are considered safe. Avoid high-dose standardised preparations during pregnancy due to lack of data.
Culinary amounts are safe; may alter taste of breast milk and occasionally affect the infant's feeding or digestion. High-dose preparations not recommended during lactation.
Avoid high-dose preparations in children — risk of gastric irritation and bleeding. Culinary amounts are unproblematic. Topical application not recommended due to burn risk.
Drug interactions
Antikoagulanzien und Thrombozytenaggregationshemmer (Warfarin, Phenprocoumon, DOAKs, ASS, Clopidogrel)
Allicin and ajoene inhibit platelet aggregation and may increase bleeding tendency; case reports describe INR elevation under warfarin.
HIV-Proteaseinhibitoren (Saquinavir, Ritonavir, Darunavir)
Garlic preparations induce CYP3A4 and P-glycoprotein; plasma levels of protease inhibitors fall markedly, with risk of treatment failure.
Antihypertensiva und Antidiabetika
Possibly additive lowering of blood pressure and blood glucose; monitor closely when combined.
Ciclosporin
Garlic preparations can lower ciclosporin plasma levels (enzyme induction); transplant patients should avoid high-dose garlic.
Contraindications
- Known Allium allergy. Discontinue 7-10 days before planned surgery (bleeding risk due to platelet aggregation inhibition). Caution with ongoing anticoagulation, bleeding disorders and HIV protease inhibitor therapy.
Harvested part: bulb (summer)
- Time of day:
- Harvest from mid-July to August once about two-thirds of the foliage has yellowed and bent over. Earlier harvest yields poorly developed cloves; late harvest causes outer tunics to split and reduces storage life.
- Drying:
- Cure bulbs with foliage for 2-4 weeks in an airy, shaded, dry place at 20-25 °C (braided or on trays). Then trim foliage and roots and store cool (5-10 °C), dry and dark; keeps for several months.
- Time of day:
- Cut young garlic greens and flower scapes in late spring (April-June) before bulb formation; the earlier, the milder the flavour.
- Drying:
- Use fresh (pesto, salad, spreads); for storage freeze or pickle in oil. Drying leads to a marked loss of aroma.
- Alliin (S-Allyl-L-cysteinsulfoxid)OtherContent: 0.5-1.8 % in frischer Zwiebel
Odourless sulphur-containing amino acid; precursor of allicin. Cleaved enzymatically to allicin by alliinase upon cutting or crushing.
- Allicin (Diallylthiosulfinat)OtherContent: bis ca. 0.4 % nach Zerkleinerung (kurzlebig)
Characteristic sulphur thiosulphinate, responsible for odour and pungency. Antimicrobial, anti-platelet, lipid-lowering. Very unstable — rapidly decomposes to diallyl sulphides, vinyldithiins and ajoene.
- Ajoen (E- und Z-Ajoen)OtherContent: Spurenmengen bis ca. 0.1 % in öligen Auszügen
Secondary breakdown product of allicin in oily media. Strongly antiplatelet, antifungal; contributes substantially to cardiovascular effects of oil-based garlic preparations.
- Diallylsulfide (DADS, DATS, Diallylsulfid)Essential oilContent: Hauptbestandteile des ätherischen Öls (ca. 0.1-0.2 % der Frischdroge)
Lipophilic polysulphides from allicin breakdown, enriched in garlic oil. Antimicrobial, antioxidant and chemopreventive effects described in vitro and in animal studies.
- γ-Glutamyl-S-allyl-L-cysteineOtherContent: 0.1-0.5 % in der getrockneten Droge
Water-soluble sulphur compound, storage substance of the bulb; key marker in aged garlic extract (AGE), there converted to S-allylcysteine.
- Saponine (z. B. Eruboside B, Sativoside B1)SaponinContent: ca. 0.05-0.1 %
Steroidal saponins with cholesterol-lowering and mild haemolytic properties; contribute to the overall lipid-lowering effect.
- Fructane (Inulin-Typ)PolysaccharideContent: ca. 11-15 % der Frischdroge
Inulin-type storage carbohydrates; prebiotic, support a favourable gut flora. In FODMAP-sensitive individuals a source of bloating.
- Adenosin und NikotinsäureOtherContent: Spurenmengen
Adenosine is considered a cofactor of the vasodilatory and platelet-modulating effect; complements the organosulphur profile.
- [1]MonographEMA/HMPC — European Union herbal monograph on Allium sativum L., bulbus (final)(accessed: 2026-05-19)
- [2]MonographKommission E Monographie — Allii sativi bulbus (Knoblauchzwiebel), BAnz Nr. 122 vom 06.07.1988(accessed: 2026-05-19)
- [3]MonographESCOP Monographs — Allii sativi bulbus / Garlic (2nd edition, online updates)(accessed: 2026-05-19)
- [4]MonographWHO Monographs on Selected Medicinal Plants, Vol. 1 — Bulbus Allii Sativi (1999)(accessed: 2026-05-19)
- [5]MonographRied K. — Garlic Lowers Blood Pressure in Hypertensive Individuals, Regulates Serum Cholesterol, and Stimulates Immunity: An Updated Meta-analysis and Review (J Nutr 2016;146(2):389S-396S)(accessed: 2026-05-19)
- [6]MonographPlants for a Future — Allium sativum L.(accessed: 2026-05-19)
- [7]MonographHeilkräuter-Lexikon — Knoblauch (Allium sativum)(accessed: 2026-05-19)
- [9]MonographASPCA Animal Poison Control — Garlic (Allium sativum)(accessed: 2026-08-10)
- [10]MonographCliniTox Giftpflanzen — Allium sativum L.: stark giftig ++ (Institut für Veterinärpharmakologie und -toxikologie, Universität Zürich)(accessed: 2026-08-10)
- [8]WikipediaWikipedia (DE) — Knoblauch(accessed: 2026-05-19)
Distribution in Europe
🤝 Permaculture Partners
In your garden, this plant acts as:
✨ Best symbiotic partners
- 🌿 Dill Classic companion-planting partner.
- 🌿 Apium graveolens Classic companion-planting partner.
- 🌿 Calendula officinalis Classic companion-planting partner.
- 🌿 Capsicum annuum Garlic deters spider mites and fungi.
- 🌿 Carrot Garlic deters carrot fly and fungi.
- 🌿 Eruca sativa Classic companion-planting partner.
- 🌿 Fragaria vesca Garlic deters strawberry fungi (grey mould).
- 🌿 Matricaria chamomilla Chamomile strengthens garlic and deters root fungi.
- 🌿 Catnip Classic companion-planting partner.
- 🌿 Basil Garlic protects basil from fungi.
- 🌿 Ocimum tenuiflorum Classic companion-planting partner.
- 🌿 Parsley Classic companion-planting partner.
- 🌿 Rhubarb Garlic deters rhubarb pests and root fungi.
- 🌿 Tomato Classic: garlic in every tomato bed — deters mildew.
- 🌿 Tagetes patula Classic companion-planting partner.
- 🌿 Tanacetum parthenium Classic companion-planting partner.
- 🌿 Tropaeolum majus Classic companion-planting partner.
⚠️ Better not planted together
- 🥬 Phaseolus vulgaris Classic companion-planting partner.
- 🥬 Phaseolus vulgaris Alliums inhibit legumes (classic rule).
- 🥬 Snap pea Classic companion-planting partner.
- 🥬 Pea Classic companion-planting partner.
- 🥬 Salvia officinalis Classic companion-planting partner.
- 🥬 Summer savory Classic companion-planting partner.
- 🥬 Fenugreek Classic companion-planting partner.
📦 Part of these planting sets:
Source: Gertrud Franck, Gesunder Garten durch Mischkultur (1980, eigene Kuration) | Helga und Margarete Langerhorst, Mein gesunder Naturgarten (eigene Kuration)