The basil in pesto and caprese is sweet basil, Ocimum basilicum, a member of the mint family. It is not holy basil, or tulsi (Ocimum tenuiflorum), a separate species used in Ayurvedic medicine. The difference matters here, because much of the human research that turns up under the name basil is on tulsi.
Not all sweet basil smells alike. Its aroma comes from oils such as eugenol, methyl eugenol, linalool, estragole and methyl cinnamate, and the mix changes a lot from one variety to another. Drying loses the most fragrant notes, and heat quickly dulls the fresh flavor, so cooks add the leaves at the end.
A spoonful of fresh leaves is mostly water. Two tablespoons (5.3 g) hold about 1 calorie and 22 µg of vitamin K, which is 18% of the daily value. Most of the research below used capsules, syrup, extracts or oils, not leaves, so it says little about the basil on your plate.
Health benefits of basil
The top findings from 16 studies, strongest evidence first
What the stars mean
- Strong. Several randomized trials, pooled in a meta-analysis, point the same way, or regulators (FDA or EFSA) have approved the claim.
- Moderate. Good randomized trials support it, but there are fewer of them, or their results vary.
- Limited. Small, short or single trials, or mixed results. Promising, but it needs confirmation.
Population and lab studies get no stars: they show a link or a mechanism, not proof.
How we rate evidence →- ★Better sleep with basil extract in menopauseA capsule with 250 mg of basil leaf extract a day for 1 month improved sleep quality and insomnia scores in 60 menopausal women. The sleep score was 3.7 against 9.1 on placebo (lower is better).
- ★Fewer menopause symptoms with basil extractIn 60 women, a 500 mg basil leaf extract capsule a day for 1 month lowered symptom scores to 6.9, against 11.3 on placebo. There was no clear difference after 2 weeks.
- ★Lower anxiety scores in people with depressionA basil syrup for 4 weeks lowered anxiety scores more than placebo in 60 people with major depression. Depression scores fell more than on placebo too.
- ★Fewer, milder migraines with basil oil on skinBasil essential oil rubbed on the skin every 8 hours reduced the pain and frequency of migraine attacks over 3 months in 144 people. The effect grew with oil strength, and everyone also took acetaminophen.
- ★No help for postpartum depression or sleepTwo capsules a day of basil leaf powder for 8 weeks after birth did not prevent postpartum depression or improve sleep quality in 78 women.
All 16 studies, strongest evidence first
A pasta meal with 100 g of basil pesto left a breakdown product of the plant compound methyleugenol in the urine of all 12 people, but only a tiny share of the intake
Controlled exposure study by researchers at Germany’s BfR risk agency and the University of Potsdam. The pesto came from a basil cultivar grown for its methyleugenol content and held 1.7 mg, and urine was collected for 48 hours. Excretion peaked 2 to 6 hours after the meal and was only 1 to 85 ppm of the intake. Methyleugenol causes cancer in rodents, so this is a safety marker, not a health benefit.
Two capsules a day of dried basil leaf powder for 8 weeks after birth did not prevent postpartum depression or improve sleep quality
Triple-blind trial in 78 women, compared with 500 mg of starch. The median depression score was 1.0 in both groups and sleep scores did not differ. The authors suggest testing higher doses and extracts.
A basil syrup for 4 weeks lowered anxiety scores in people with major depression compared with placebo
Single-blind trial in 60 people with major depressive disorder, rated on the Hamilton Anxiety scale and the Beck Depression Inventory. Depression scores fell more than on placebo too. The abstract gives no scores or dose, and the authors call for larger, longer studies.
A capsule with 250 mg of basil leaf extract a day for 1 month improved sleep quality and insomnia scores in menopausal women
Triple-blind trial in 60 women aged 40 to 65. After 1 month the sleep quality score was 3.7 against 9.1 on placebo, and the insomnia severity score 5.6 against 11.0 (lower is better). This was an extract in capsules, not leaves.
A capsule with 500 mg of basil leaf extract a day for 1 month lowered menopause symptom scores to 6.9, against 11.3 on placebo
Triple-blind trial in 60 women using the Menopause Rating Scale. There was no clear difference after 2 weeks (9.5 against 11.2, p = 0.163), so the gap appeared only at the 1 month mark. Same research group as the sleep trial above, and again an extract in capsules.
A mouthwash with 30% basil lowered gum inflammation and plaque scores over 21 days, though chlorhexidine lowered them further
Double-blind trial in 70 adults with plaque-induced gingivitis, 35 per group, comparing the basil mouthwash with 0.2% chlorhexidine as an add-on to toothbrushing. The authors call the basil mouthwash non-inferior despite the gap. This is a mouthwash, not food.
Basil essential oil rubbed on the skin reduced the pain and frequency of migraine attacks over 3 months, more at higher strengths
Triple-blind trial in 144 people with migraine, in four groups of 36 (2%, 4% or 6% oil, or placebo), applied every 8 hours. Everyone also took 325 mg of acetaminophen every 12 hours. The abstract gives no pain scores, only that the effect grew over time and with strength.
A traditional basil oil rubbed on the knee eased osteoarthritis symptoms about as much as diclofenac gel over 4 weeks
Double-blind trial in 100 people with knee osteoarthritis, using basil oil made with sesame oil or diclofenac gel 3 times a day. The groups did not differ, and both improved. There was no placebo group, so the oil cannot be credited with the improvement alone.
Basil seeds (not the leaves), 10 g a day for 12 weeks, did not change weight or body fat compared with the control group in people with fatty liver
Single-blind trial in people with fatty liver disease in four groups: basil seeds, psyllium, a mix of both, or no treatment. Weight and BMI fell within the treated groups, but the differences between groups were not significant. Basil seeds, called sabja, are a different product from the leaves.
HOLY BASIL (TULSI), a different plant: a review of 24 human studies found favorable results in all of them and no significant side effects
Systematic review of human studies of tulsi, Ocimum tenuiflorum, not the sweet basil in your kitchen. The studies covered metabolic disorders, heart disease, immunity and brain function. The authors say the dose and form still need to be clarified.
HOLY BASIL (TULSI), a different plant: its leaves lowered fasting blood glucose by 21 mg/dL in people with type 2 diabetes
Single-blind, placebo-controlled crossover trial of holy basil leaves, Ocimum sanctum, not sweet basil. Fasting glucose fell 17.6% and after-meal glucose 15.8 mg/dL (7.3%). The abstract does not give the number of people or the dose, and the trial is from 1996.
Fresh basil leaves mixed into chow for 2 to 8 months prevented memory decline in old female mice, but did nothing in younger ones
Mouse study, so it says nothing certain about people. In 18-month-old mice, basil improved object recognition and maze performance compared with controls. In 8-month-old mice it did not change cognition. The abstract does not give the amount of leaves.
Sweet basil powder at 1% of the diet for 12 weeks lowered body weight and liver weight in obese mice
Mice on a high-fat, high-sucrose diet. Food intake and fat pad weights did not differ, and a gene linked to inflammation in belly fat was lower with basil. It was a mouse study of the dried herb, not a trial in people.
A week of basil water extract lowered blood glucose in healthy rats and in rats made diabetic
Rat study of an aqueous basil extract given for 7 days. The extract also lowered a marker of fat damage (lipid peroxidation) and raised antioxidant enzyme activity. The abstract gives no dose, and no trial of sweet basil on blood sugar in people was found.
A basil water extract cut clot weight in rats from 48.1 to 19.0 mg at 75 mg/kg a day, about the same effect as aspirin
Rats got 15, 75 or 375 mg/kg of the extract for 2 weeks, and platelet clumping fell in step with dose. The effect faded 3 to 7 days after stopping. It is an extract in rats, and whether basil leaves do this in people is not known.
A basil ethanol extract at 60 µg/ml cut new cholesterol made by human macrophages by about 60%
Cell study on human immune cells that take up modified LDL. The extract also made LDL more resistant to oxidation, but 20 µg/ml did not lower cholesterol synthesis. No animals or people were involved.
Who should be careful with basil
Most people can eat basil freely. Take a little care if one of these applies:
- Warfarin. Basil contains vitamin K, which can change how this blood thinner works: 2 tbsp of fresh leaves give 22 µg, and a pesto holds far more. You do not need to avoid it; keep the amount steady and ask your clinic before big changes.
- Large daily amounts, oils and extracts. Basil contains estragole and methyleugenol, which caused cancer in animal tests. Germany’s risk agency (BgVV, now BfR) found no proven harm to people in 2002 and suggested only limiting steady, long-term use beyond occasional kitchen amounts; for herbal medicines, the EU’s EMA advises pregnant and breastfeeding women against products above 0.05 mg of estragole a day.
How to choose, store and eat basil
- Fresh leaves: 2 tbsp (5.3 g) hold about 1 calorie and 22 µg of vitamin K, 18% of the daily value, and heat dulls the flavor fast, so add them at the end.
- Dried: drying loses basil’s most fragrant notes, so dried and fresh basil are not an even swap for flavor.
- Pesto and supplements: pesto packs many leaves into one dish, and the trials above used extract capsules of 250 to 500 mg a day, which are not the same as cooking with leaves.
Keep fresh basil out of the cold. In a lab test, sweet basil leaves stored at 4°C (39°F) for 9 days showed chilling injury and lost polyphenols and antioxidant capacity, while leaves stored at 12°C (54°F) kept them. A cool spot on the counter suits it better than the fridge door.
Sources
- Basil, fresh (FDC ID 172232). USDA FoodData Central.
- Dietary advice for patients taking warfarin. Cambridge University Hospitals NHS Foundation Trust.
- Anticoagulant medicines: considerations. NHS.
- Minimierung von Estragol- und Methyleugenol-Gehalten in Lebensmitteln (background paper of 15 January 2002). BgVV, now the German Federal Institute for Risk Assessment (BfR).
- Public statement on the use of herbal medicinal products containing estragole, EMA/HMPC/137212/2005 Rev 1 Corr 1. European Medicines Agency, 2023.
- Sestili P, Ismail T, Calcabrini C, et al. The potential effects of Ocimum basilicum on health: a review of pharmacological and toxicological studies. Expert Opin Drug Metab Toxicol. 2018.
- Fratianni F, Cefola M, Pace B, et al. Changes in visual quality, physiological and biochemical parameters assessed during the postharvest storage at chilling or non-chilling temperatures of three sweet basil cultivars. Food Chem. 2017.
- Spence C. Sweet basil: an increasingly popular culinary herb. Int J Gastron Food Sci. 2024.
- Basil. Wikipedia.
History of basil
Basil is native to India and other warm regions from Southeast Asia to northern Australia, and people have since carried it around the world. Its name comes from the Greek basilikón phytón, the “royal” or “kingly” plant, and the French still call it the royal herb.
It was a plant of ritual and medicine long before it was a food. In places such as Greece and Bulgaria its strong scent and its antimicrobial properties feature in religious practice. In the 14th century Boccaccio’s Decameron used a pot of basil as a plot device, and John Keats later retold the story in his poem “Isabella, or the Pot of Basil.”
The surprise is how late the kitchen came to it. A 2024 review notes that before the 20th century basil was rarely used as a culinary herb in the United States, in Britain, or even in Italy. It may be one of the few herbs adopted into cooking mainly because it tastes good.
Pesto is the dish that made it famous. The word comes from the Genoese verb pestâ, to pound, because the leaves are crushed in a marble mortar with a wooden pestle. One of the first documented basil-based recipes appeared in Giovanni Battista Ratto’s La Cuciniera Genovese in 1863.
Several plants share the name. Thai basil is a variety of Ocimum basilicum, while holy basil is a separate species, Ocimum tenuiflorum, formerly called Ocimum sanctum. Lemon basil is a hybrid.
Sources
- Spence C. Sweet basil: an increasingly popular culinary herb. Int J Gastron Food Sci. 2024.
- Basil. Wikipedia.
- Pesto. Wikipedia.
- Jamshidi N, Cohen MM. The clinical efficacy and safety of tulsi in humans: a systematic review of the literature. Evid Based Complement Alternat Med. 2017.
Frequently asked questions about basil
Is basil good for you?
In the amounts people eat, it is a safe herb for most people, and its health benefits are unproven. Two tablespoons (5.3 g) of fresh leaves give about 1 calorie and 22 µg of vitamin K (18% of the daily value). The trials of sweet basil above are small and used capsules, syrup, extracts or oils, and none reaches moderate evidence.
Is sweet basil the same as holy basil (tulsi)?
No. Sweet basil is Ocimum basilicum, the herb in pesto, while holy basil or tulsi is Ocimum tenuiflorum, a separate species from Ayurvedic medicine. A review found 24 human studies of tulsi, but those results do not transfer to sweet basil. This page labels the two tulsi cards so they are not mistaken for kitchen basil.
How many calories and how much vitamin K are in basil?
Very few calories and a good amount of vitamin K. Two tablespoons (5.3 g) of fresh basil have about 1 calorie, 0.2 g of protein, 0.1 g of fiber and 22 µg of vitamin K, which is 18% of the daily value (29% of the EU reference intake). A full 100 g, far more than anyone eats as a herb, has 23 calories and 415 µg of vitamin K.
Can you eat basil if you take warfarin?
Yes, in steady amounts. Two tablespoons of fresh leaves hold 22 µg of vitamin K, and a pesto holds much more. The NHS says to keep the amount of vitamin K foods you eat consistent, not to avoid them, so tell your clinic before you change how much basil or pesto you eat.
Is basil safe to eat every day?
For normal cooking amounts, yes, with one note. Basil contains estragole and methyleugenol, which caused cancer in animal tests, and in 2002 Germany’s BgVV (now BfR) found no proven harm to people but suggested limiting steady, long-term use beyond occasional kitchen amounts. A 2018 review judged basil in food safe and saw concern mainly for essential oils. In the one human study, a meal with 100 g of pesto left only a trace of a methyleugenol breakdown product in the urine.
Does basil help with anxiety or sleep?
Maybe, but the evidence is thin. A basil syrup lowered anxiety scores in 60 people with major depression over 4 weeks, and 250 mg a day of extract capsules improved sleep scores in 60 menopausal women. Dried leaf powder capsules did not change sleep quality in 78 new mothers. All were small trials, and none tested basil as a food.
Does basil lower blood sugar?
No trial of sweet basil on blood sugar in people was found. A water extract lowered glucose in healthy and diabetic rats, which is not proof for people. The only human glucose trial here used holy basil leaves in 1996, and fasting glucose fell by 21 mg/dL, but that is tulsi, not kitchen basil. Ask your care team before using basil to manage diabetes.
What are basil seeds, and are they the same as the leaves?
No. Basil seeds, also called sabja, are a different product from the leaves, so the nutrition and the research differ. In one trial, 10 g a day of basil seeds for 12 weeks did not change weight or body fat compared with a control group in people with fatty liver. This page has no nutrition numbers for the seeds.