← The ApothecaryLamiaceaeleaves, aerial parts, seeds, essential oilFact-checked 24 October 2026

EvidenceLimited evidence

SafetyUse with caution

PregnancyInsufficient data

Actions

carminative · anti-inflammatory · analgesic · antibacterial · antioxidant

What the regulators say

No EU herbal monograph (not in EMA’s overview EMA/HMPC/228356/2012 Rev. 2) or WHO monograph for sweet basil was found (WHO volume 2 covers holy basil, a different species). EMA's HMPC public statement on estragole (EMEA/HMPC/137212/2005) lists sweet basil essential oil at 5–85% estragole and the plant at 238–8,780 ppm, concludes that short-term use of herbal medicines at recommended doses in adults does not pose a significant cancer risk, and asks that exposure of young children and pregnant and breastfeeding women be minimised. Not evaluated by IUCN (via GBIF); widely cultivated.

Sweet basil

Ocimum basilicum

Also calledKemangi (Indonesian)

The familiar kitchen herb, used medicinally from India and Southeast Asia to Persia and Africa for colds, coughs, fever and digestive complaints. A handful of small Iranian and Indian trials have tested basil syrup for anxiety, basil oil for knee osteoarthritis and basil mouthwash for gingivitis; the essential oil can contain large amounts of estragole, a compound EMA treats as a genotoxic carcinogen.

What it is used for

Anxiety and nervous tension
Limited
In a single-blind trial of 60 people with major depression, a basil leaf-extract syrup (1,100 mg per 5 ml) taken for 4 weeks alongside usual treatment reduced anxiety and depression scores more than placebo. One small trial.¹
Arthritis and joint pain
Limited
In a double-blind trial of 100 people with knee osteoarthritis, a traditional Persian basil-in-sesame oil rubbed on three times daily for 4 weeks performed no differently from diclofenac gel; both groups improved. There was no placebo group.²
Mouth ulcers and gum health
Limited
In a double-blind trial of 70 adults with plaque-induced gingivitis, a 30% basil mouthwash used with toothbrushing for 21 days was non-inferior to 0.2% chlorhexidine for reducing gum inflammation and plaque.³
Wind, bloating and colic
Traditional
Avicenna, Rhazes and the 18th-century Persian author Salehi Heravi mention basil for bloating and haemorrhoids; healers in southern Thailand use it for flatulence. Not tested in trials.^2,4
Cough
Traditional
Leaf and seed decoctions are used for cough, colds and fever by healers in several districts of India and Nepal. A review of respiratory effects found mainly laboratory and animal studies and very few clinical studies.^4,5
Fever
Traditional
Recorded in Indian ethnobotanical surveys as a leaf-and-seed decoction for fever; untested clinically.⁴

How it is prepared

syrup

A syrup made from a hydroalcoholic leaf extract, as prepared for an Iranian trial.

Talaei et al. 2025 trial: 1,100 mg extract per 5 ml syrup for 4 weeks (research preparation).

Anxiety and nervous tension

infused oil

Fresh basil leaves prepared in sesame oil according to a traditional Persian formulation and rubbed on the joint.

Askari et al. 2024 trial: applied three times daily for 4 weeks.

Arthritis and joint pain

decoction

Leaves and seeds boiled in water, as recorded among Indian traditional healers.

Cough · Fever

Amounts are as recorded by the named source, not a recommendation.

Safety

Pregnancy: Insufficient data
Breastfeeding: Insufficient data
Children: EMA (estragole statement): exposure of young children to estragole should be minimised, which applies chiefly to the essential oil and concentrated extracts.

Do not use if

Essential oil and concentrated extracts in pregnancy, breastfeeding and young children: EMA asks that estragole exposure in these groups be minimised

Side effects

In the anxiety trial, mild transient stomach discomfort and headache in a few participants
No adverse events were recorded with topical basil oil in the knee osteoarthritis trial

Toxicity

Culinary amounts are not a concern in published reviews, which attribute safety concerns mainly to the essential oil and its estragole and methyl eugenol content. Estragole is genotoxic and carcinogenic in rodents; EMA judged short-term adult use of herbal medicines at normal doses not to pose a significant cancer risk but called for further studies and noted that skin absorption has not been assessed. A 2018 review recommended a precautionary limit on these compounds in basil oils and use of low-estragole chemotypes.

In the healing traditions

Persian medicine
Basil
Described as reducing inflammation and easing bloating and haemorrhoids; a traditional oil of basil in sesame is used on painful joints.
Avicenna; Rhazes; Salehi Heravi (18th century), as cited by Askari et al. 2024
Indian folk medicine
Basil
The review notes use in the Ayurvedic and Unani systems; in surveys of Indian traditional healers (Uttarakhand, Odisha, Assam, Sikkim, Kerala) leaves and seeds are given as decoctions, pastes or juice for fever, cough, colds, urinary problems, constipation, headache, insomnia and diarrhoea.
Southeast Asian (Jamu, Thai, Philippine…)
Basil
Thai healers in Phatthalung use it for flatulence and peptic ulcer; in Mindanao, Philippines, leaves are rubbed on cold sores.

Active compounds

estragole (methyl chavicol): phenylpropanoid that can make up 5–85% of the essential oil depending on chemotype; EMA considers it a naturally occurring genotoxic carcinogen
linalool: major monoterpene alcohol of many basil oils
eugenol and methyl eugenol: phenylpropanoids of the oil
rosmarinic acid and other polyphenols: phenolic constituents of the leaf

History

Basil was described by Avicenna and Rhazes among the medieval Persian physicians, and a basil-in-sesame oil from Persian medicine was tested against diclofenac gel in a 2024 Iranian trial. Basil is thought to be native to Asia and Africa, and tradition holds that Alexander the Great brought it from India to Greece.

Sources

Reference, not prescription. Nothing here is medical advice. Herbs can interact with medicines and be dangerous in pregnancy; tell your doctor or pharmacist about anything you take.