Clove
The "fragrant rivet" — eugenol, antimicrobial power, and the science of the toothache tradition.
In 1 minute
What does it provide? Eugenol (70–90% of the essential oil) and β-caryophyllene — antimicrobial, local anesthetic, anti-inflammatory, and antioxidant.
How much? In the kitchen, 1–4 whole clove buds (≈ 0.1–0.3 g) per meal. Traditional topical use: 1 drop of clove oil for toothache (short-term).
When to avoid? Alongside anticoagulants in high-dose extract, in pregnancy the essential oil internally, in infants topically, eugenol sensitivity, in liver disease as a high-dose supplement.
Clove originally is native to the Maluku Islands (today's Indonesia), and around 200 BCE already appears in Chinese imperial sources — during the Han dynasty, officials chewed clove in their mouths before imperial audiences so that their breath would be fragrant. It reached the Greco-Roman world in Pliny's time as part of "Indian pepper" blends. Medieval Arab physicians (Avicenna) recommended it for digestive complaints, and it was one of the most expensive spices on the Silk Road — at the end of the 13th century, Marco Polo separately mentions it in his Venetian travelogue.
The 16th–17th century is clove's "golden age": the Portuguese, then Dutch, colonial empires warred over a monopoly on the Maluku Islands. The Dutch East India Company in 1652 staged bloody destruction to monopolize clove cultivation — all clove trees outside the island of Ambon were destroyed. The monopoly was broken in 1770, when a French colonial official, Pierre Poivre, smuggled seedlings out to Mauritius and Zanzibar. Research on chemical activity began in 1858 with the isolation of eugenol, and in 20th-century dentistry, clove oil (the classic "zinc-oxide-eugenol" filling) became a standard local anesthetic. **(BMC Complement, J Ethnopharmacol)
🔬 Scientific Background
Clove's main bioactive is eugenol (4-allyl-2-methoxyphenol), which makes up 70–90% of the bud's essential oil — this is one of the most concentrated natural eugenol sources. Eugenol acts through several parallel mechanisms: TRPV1 and TRPA1 receptor modulation (local anesthesia), NF-κB inhibition (anti-inflammation), and very strong antimicrobial activity against Gram-positive and Gram-negative bacteria, as well as Candida albicans.
The dental local anesthetic effect is clinically confirmed — in a randomized double-blind trial (Alqareer 2006), clove gel reduced injection needle-prick pain equivalently to benzocaine. "Zinc-oxide-eugenol" paste is still used today for dental fillings and root canal treatments.
Its antimicrobial spectrum in vitro is impressive: effective against food pathogens (Listeria, Salmonella, E. coli), H. pylori, and oral microbiome pathogens (Streptococcus mutans). Clinically, however, it is not an antibiotic substitute.
Anticoagulant effect: eugenol inhibits platelet aggregation and prostaglandin synthesis — high-dose supplementation alongside anticoagulant therapy adds bleeding risk.
At the microbiome level, eugenol's selective antimicrobial effect in mouse models in vivo showed relative growth of Lactobacillus and support of commensal balance.
- + Cinnamon, cardamom, clove, pepper (chai/garam masala): classic Indian synergy.
- + Hot drink (mulled wine, tea, chocolate): essential oil dissolves well.
- + Meat marinade: antimicrobial preservation + flavor depth.
- + Honey (for toothache): 1 drop of clove oil + 1 tsp of honey, short-term topical relief.
- + Baked goods (lebkuchen, gingerbread): classic Christmas pattern.
- + Polyphenol-rich matrix (red wine, red berries): flavor harmony + antioxidant synergy.
- Anticoagulants (warfarin, DOAC, aspirin, clopidogrel) + high-dose clove extract: additive bleeding risk.
- Eugenol oil held in larger amounts under the tongue: severe oral mucosa irritation, burn injury.
- Applied in the mouth of an infant: severe hepatotoxicity cases documented (USA, FDA warning).
- Heated eugenol oil + open wound: tissue irritation, possible necrosis.
- Long simmer (30+ min at high heat): essential oil evaporates.
- Concentrated extract on empty stomach: GI irritation.
- Coagulation disorder, anticoagulant therapy: high-dose supplement to be avoided.
- Infant (< 2 years): topical clove oil for toothache to be avoided — hepatotoxicity cases.
- Pregnancy, breastfeeding: essential oil internally to be avoided, culinary dose safe.
- Active gastric ulcer: concentrated extract irritates.
- Eugenol allergy (contact cheilitis): topical avoidance.
- Severe liver disease: high-dose supplement to be avoided.
- Planned surgery within 2 weeks: stop high-dose supplement.
- G6PD deficiency: theoretical hemolysis trigger at high-dose eugenol.
Daily serving
1–4 whole clove buds (≈ 0.1–0.3 g) per meal; in ground form ¼–½ tsp for baking recipes.
Preparation pattern
- Whole bud: in mulled drink, in sauce, 5–10 min — essential oil dissolves well.
- Studding an onion with clove: bay leaf + clove + onion → classic "bouquet garni" for meat stock.
- In baking, can be added directly into the dough (lebkuchen, gingerbread).
- Remove the whole buds before serving — so they don't accidentally crack under a guest's tooth.
Classic patterns
Mulled wine: red wine + clove + cinnamon + nutmeg + orange peel + sugar.
Garam masala: clove + cinnamon + cardamom + cumin + pepper.
Ham glaze: roast ham + studded clove + brown sugar + Dijon mustard.
Pho (Vietnamese soup): clove + anise + cinnamon + ginger + beef bone broth.
Storage and what to avoid
Storage: whole bud 2 years, airtight, in a dark place; ground powder 6 months.
What not to do: don't give clove oil to an infant, don't arbitrarily combine clinical-dose supplements with warfarin, don't swallow the whole bud (not dangerous, but can be tooth-damaging).
References
[1] Alqareer A et al. The effect of clove and benzocaine versus placebo as topical anesthetics. J Dent 2006;34(10):747–750.
[2] Cortés-Rojas DF et al. Clove (Syzygium aromaticum): a precious spice. Asian Pac J Trop Biomed 2014;4(2):90–96.
[3] Pulikottil SJ, Nath S. Potential of clove of Syzygium aromaticum in development of a therapeutic agent for periodontal disease: a review. South Afr Dent J 2015;70(3):108–115.
[4] FDA. Clove oil — pediatric warning notice.
[5] Chaieb K et al. The chemical composition and biological activity of clove essential oil, Eugenia caryophyllata. Phytother Res 2007;21(6):501–506.
[6] Pramod K et al. Eugenol: a natural compound with versatile pharmacological actions. Nat Prod Commun 2010;5(12):1999–2006.
[7] Xu JG et al. Clove oil — Helicobacter pylori in vitro. Helicobacter 2015.