Basil (Ocimum basilicum): Uses, Evidence and Safety
Sweet basil (Ocimum basilicum): food use versus extracts, three small trials, the estragole question raised by EU regulators, pregnancy cautions, and holy basil compared.
Content last updated . This page has not been medically reviewed.
Safety first. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.
Safety first. Basil as a food is not the concern here. The caution is about concentrated forms. Basil contains estragole, and the US LactMed database says many sources recommend that medicinal doses of basil not be used during breastfeeding because of its estragole content and a lack of safety information. [1] The EU's herbal medicines committee (HMPC) has also said that exposure to estragole from herbal products should be minimized for young children and for pregnant and breastfeeding women. [2] Basil essential oil has high estragole content and is covered separately at Basil and Marjoram Oils. This page gives no instructions for swallowing essential oils.
What basil is, and what it is not
This page is about sweet basil, Ocimum basilicum. GBIF accepts Ocimum basilicum L. in the family Lamiaceae (the mint family). [3] The parts used are the leaves, seeds and the oil. LactMed lists linalool, 1,8-cineole, methylchavicol and methylcinnamate among its compounds, along with an essential oil with high estragole content. [1]Holy basil, also called tulsi, is a different plant with its own pages: Holy Basil (Tulsi) and Tulsi Tea. Results for tulsi do not carry over to sweet basil, and the reverse.
Traditional use
This is tradition, not proof. LactMed says basil is a purported galactogogue (a substance said to increase milk supply), but has also been used to decrease breastmilk oversupply in Persian traditional medicine, and that no scientifically valid clinical trials support either use. [1] The sources we read do not describe other traditions, so we do not.What research shows
All the human trials we found for sweet basil are small, and each tested a leaf extract capsule or a syrup, not the fresh herb used in cooking.| Use | What the source found | Strength of evidence | Population and form studied |
|---|---|---|---|
| Sleep in menopause | In a triple-blind randomized trial, sleep quality and insomnia scores improved more with basil leaf extract capsules than with placebo after 2 weeks and 1 month. [4] | Promising but limited (one small trial) | 60 Iranian women aged 40 to 65; capsules with 250 mg of extract plus 250 mg of a second ingredient |
| Menopausal symptoms | After 1 month, symptom scores were lower in the basil group than the placebo group; at 2 weeks the difference was not significant. [5] | Promising but limited (one small trial) | 60 menopausal women; a 500 mg leaf extract capsule or placebo, 1 month |
| Anxiety in major depressive disorder | In a single-blinded randomized trial, anxiety and depression scores fell more with basil syrup than with placebo over 4 weeks. The authors call for larger, longer studies. [6] | Promising but limited (single-blinded, small) | 60 people with major depressive disorder; syrup |
| Basil seeds (for blood sugar, weight, digestion) | Proper evidence not found: our PubMed searches (basil seed or seeds with randomized and human terms) returned laboratory and food-technology studies, not human trials. | Insufficient evidence | None identified |
| Blood sugar, cholesterol, immunity, cleanse claims | Proper evidence not found in the sources we read. | Marketing claim | None identified |
None of these trials is a reason to treat sleep problems, menopause symptoms or anxiety with basil instead of care from a clinician. See Herbs for Sleep and Herbs for Anxiety and Stress for how the evidence compares across herbs.
The estragole question
Estragole is a natural compound found in several plants, and EMA's Committee on Herbal Medicinal Products lists sweet basil among the plants that contain it. [2] The committee's 2005 statement, revisited in a 2014 draft revision, concluded that estragole is a naturally occurring genotoxic carcinogen (a substance that can damage DNA and cause cancer), with a DNA potency similar to safrole. [2] It also noted that these effects depend on dose, that rodent studies show them to be minimal at doses far above expected human exposure, and concluded that short-term use of herbal medicines in adults at recommended amounts does not pose a significant cancer risk. [2] LactMed adds that estragole might be a procarcinogen. [1]The statement names fennel and anise as the plants of most interest in Europe, not basil, so it gives no basil-specific limit. [2] Using basil as a seasoning is a very different exposure from a concentrated extract or oil, and the sources we read do not quantify that difference for basil.
Safety
- Pregnancy: a 2017 systematic review of herbal use in pregnancy in Asian countries put basil in its "use with caution" group: not studied in human pregnancy and not to be used in doses higher than commonly found in food. [7] See Pregnancy and Breastfeeding.
- Breastfeeding: LactMed says basil appears to be safe in the amounts found in foods, and that there are no data on its components in breastmilk or on its safety in nursing mothers or infants. [1]
- Medicines: no interaction is described in the sources we read, which is not proof that none exists. Ask a pharmacist, and see How Interactions Work.
- Allergy: the EU thyme monograph warns about allergy to plants of the mint family. [8] Basil is in that family, but no source we read describes basil allergy specifically. [3] See Herbal Allergy and Cross-Reactivity.
- Children, older adults, liver and kidney disease, bleeding, surgery: not described in the sources we read.
- Quality: LactMed notes that supplements may contain multiple ingredients and differences between labeled and actual ingredients are often found. [1] See Quality Testing and Certifications.
We give no amounts to take. A clinician or pharmacist decides what suits a person.
Frequently asked questions
Is basil good for you?
As a food it is a common seasoning, and LactMed says it appears safe in food amounts during breastfeeding. [1] Proper evidence not found that basil prevents or treats any disease; the human trials are small. [4]
Are basil seeds a health food?
Proper evidence not found. Our searches turned up no human trials of basil seeds.
Is sweet basil the same as holy basil?
No. Tulsi is a separate plant profiled in Adaptogens; research on one does not apply to the other.
What is estragole and should I worry?
It is a natural compound in basil and other plants. EU regulators concluded that short-term adult use of herbal medicines at recommended amounts does not pose a significant cancer risk, but advised minimizing exposure for young children and pregnant and breastfeeding women. [2]
Is basil safe in pregnancy?
Food amounts, according to the 2017 review; not higher amounts. [7]
References
- US National Library of Medicine, LactMed, Basil (record NBK501826, read through its PubMed entry). Read 2026-10-23.
- European Medicines Agency (EU), HMPC, Public statement on the use of herbal medicinal products containing estragole (EMA/HMPC/137212/2005, draft revision 1 released for consultation 24 November 2014; original statement adopted November 2005). Read 2026-10-23.
- GBIF Backbone Taxonomy, Ocimum basilicum match record. Read 2026-10-23.
- The effect of oral capsule of Ocimum basilicum leaf extract on sleep quality and insomnia severity in menopausal women: A randomized clinical trial. Phytotherapy Research, 2023 (abstract read). Read 2026-10-23.
- The effect of oral capsules containing Ocimum basilicum leaf extract on menopausal symptoms in women: a triple-blind randomized clinical trial. European Journal of Medical Research, 2024 (abstract read). Read 2026-10-23.
- Basil (Ocimum basilicum) to Alleviate Anxiety in Patients With Major Depressive Disorder: A Randomized Placebo-Controlled Clinical Trial. Brain and Behavior, 2025 (abstract read). Read 2026-10-23.
- Ahmed M, Hwang JH, Choi S, Han D. Safety classification of herbal medicines used among pregnant women in Asian countries: a systematic review. BMC Complementary and Alternative Medicine, 2017. Read 2026-10-23.
- European Medicines Agency (EU), HMPC, Community herbal monograph on Thymus vulgaris L. and Thymus zygis L., herba (EMA/HMPC/342332/2013, adopted 12 November 2013). Read 2026-10-23.