Botanical names:
Ocimum sanctum, Ocimum tenuiflorum

Parts Used & Where Grown

Holy basil is native to the Indian subcontinent and other parts of tropical Asia. The leaf and seed oil are used therapeutically.

What Are Star Ratings?

Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.

For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.

3 Stars Reliable and relatively consistent scientific data showing a substantial health benefit.

2 Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.

1 Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.

This supplement has been used in connection with the following health conditions:

Used for Why
2 Stars
500 mg three times per day
Animal studies have found that extracts of holy basil help keep the bronchial airway passages clear. In two trials, asthma patients who took holy basil had better breathing function and fewer attacks.

Animal studies have found that extracts of holy basil (Ocimim sanctum) inhibit constriction of the bronchial airway passages. Two preliminary clinical trials treated asthma patients with 500 mg of holy basil three times daily for one month. Breathing function improved and the frequency of attacks was reduced. Placebo-controlled research is needed to validate these results.

2 Stars
Type 2 Diabetes
1,000 to 2,500 mg daily
Taking holy basil may help people with type 2 diabetes control their blood sugar levels.
Preliminary trials of holy basil (Ocimim sanctum) leaves and hairy basil (Ocimum canum) seeds have shown that these herbs may help people with type 2 diabetes control their blood sugar levels. An uncontrolled study reported that 1,000 mg per day of holy basil lowered blood sugar, LDL (“bad”) cholesterol, and triglycerides, while a controlled trial tested 2,500 mg per day and found similar changes in blood sugar, but only minor effects on total blood cholesterol. The mechanism of action of holy basil leaf is not understood and it is unknown whether common culinary sweet basil (Ocimum basilicum) would have similar effects.
1 Star
Poison Oak/Ivy
Refer to label instructions
Holy basil has been used historically to treat skin inflammations such as poison oak and poison ivy.

A great many plants have been used historically to treat skin inflammations like poison oak and poison ivy dermatitis. Examples include calendula (Calendula officinalis), blood root (Sanguinaria canadensis), Virginia snakeroot (Aristolachia serpentaria), holy basil (Ocimum tenuifolium), and chickweed (Stellaria media). None of these remedies has been subjected to controlled clinical studies to determine if they are safe and effective for this use. Cooling essential oils, such as peppermint and menthol, have also been used topically to relieve burning pain and itch. Such oils should not be applied full-strength, but should rather be diluted (for example in lotion or gel) to avoid further skin irritation.

Traditional Use (May Not Be Supported by Scientific Studies)

Holy basil is a relative of the more familiar species used in cooking. Known to the Ayurvedic medical tradition as tulsi, it has been called the “Queen of Herbs” since the times of ancient civilization in India.1 Ayurvedic tradition classifies tulsi as an adaptogenic herb, capable of increasing the body’s resistance to stress and disease.2 , 3 Its many specific uses have included coughs, colds, and other respiratory disorders, fevers, headaches, stomach disorders, and heart disease.

How It Works

Botanical names:
Ocimum sanctum, Ocimum tenuiflorum

How It Works

The stem and leaves of holy basil contain a variety of constituents that may have biological activity, including saponins, flavonoids, triterpenoids, and tannins.4 The leaf also contains an essential oil composed of eugenol and other volatile compounds.5 Several of these constituents have antioxidant and anti-inflammatory properties according to test tube studies.6 In animal studies, extracts of holy basil leaf have also lowered blood sugar,7 , 8 reduced some measures of the response to physical stresses,9 , 10 , 11 , 12 reduced pain sensitivity,13 , 14 protected heart tissue from excessive damage due to a heart attack,15 improved wound healing,16 , 17 and protected stomach tissue from damage from aspirin.18 Large amounts of holy basil extract were used in these studies, and few of these effects have been investigated in humans.

How to Use It

Human clinical trials of holy basil typically use 1,000 to 2,500 mg per day of dried, powdered leaf, either taken all at once or divided into two or three smaller amounts.


Botanical names:
Ocimum sanctum, Ocimum tenuiflorum

Interactions with Supplements, Foods, & Other Compounds

At the time of writing, there were no well-known supplement or food interactions with this supplement.

Interactions with Medicines

As of the last update, we found no reported interactions between this supplement and medicines. It is possible that unknown interactions exist. If you take medication, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist.
The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.

Side Effects

Botanical names:
Ocimum sanctum, Ocimum tenuiflorum

Side Effects

Two animal studies suggested that large amounts of holy basil might negatively affect fertility,19 , 20 but no adverse reactions have been reported in human clinical trials. Safety during pregnancy and lactation has not been investigated; until more is known, holy basil should probably be avoided at those times.21


1. Singh N, Hoette Y. Tulsi: the mother medicine of nature. Lucknow, India: International Institute of Herbal Medicine, 2002.

2. Bhattacharya SK, Bhattacharya A, Chakrabarti A. Adaptogenic activity of Siotone, a polyherbal formulation of Ayurvedic rasayanas. Indian J Exp Biol 2000;38:119-28.

3. Wagner H, Norr H, Winterhoff H. Drugs with adaptogenic effects for strengthening the powers of resistance. Z Phytotherapie 1992;13:42-54.

4. Jaggi RK, Madaan R, Singh B. Anticonvulsant potential of holy basil, Ocimum sanctum Linn. and its cultures. Indian J Exp Biol 2003;41:1329-33.

5. Kelm MA, Nair MG, Strasburg GM, DeWitt DL. Antioxidant and cyclooxygenase inhibitory phenolic compounds from Ocimum sanctum Linn. Phytomedicine 2000;7:7-13.

6. Kelm MA, Nair MG, Strasburg GM, DeWitt DL. Antioxidant and cyclooxygenase inhibitory phenolic compounds from Ocimum sanctum Linn. Phytomedicine 2000;7:7-13.

7. Vats V, Grover JK, Rathi SS. Evaluation of anti-hyperglycemic and hypoglycemic effect of Trigonella foenum-graecum Linn, Ocimum sanctum Linn and Pterocarpus marsupium Linn in normal and alloxanized diabetic rats. J Ethnopharmacol 2002;79:95-100.

8. Kar A, Choudhary BK, Bandyopadhyay NG. Comparative evaluation of hypoglycaemic activity of some Indian medicinal plants in alloxan diabetic rats. J Ethnopharmacol 2003;84:105-8.

9. Bhargava KP, Singh N. Anti-stress activity of Ocimum sanctum Linn. Indian J Med Res 1981;73:443-51.

10. Sembulingam K, Sembulingam P, Namasivayam A. Effect of Ocimum sanctum Linn on noise induced changes in plasma corticosterone level. Indian J Physiol Pharmacol 1997;41:139-43.

11. Singh N. A pharmaco-clinical evaluation of some Ayurvedic crude plant drugs as anti-stress agents and their usefulness in some stress diseases of man. Ann Nat Acad Ind Med 1986;1:14-26.

12. Sood S, Narang D, Thomas MK, et al. Effect of Ocimum sanctum Linn. on cardiac changes in rats subjected to chronic restraint stress. J Ethnopharmacol 2006;108:423-7.

13. Khanna N, Bhatia J. Antinociceptive action of Ocimum sanctum (Tulsi) in mice: possible mechanisms involved. J Ethnopharmacol 2003;88:293-6.

14. Godhwani S, Godhwani JL, Vyas DS. Ocimum sanctum: an experimental study evaluating its anti-inflammatory, analgesic and antipyretic activity in animals. J Ethnopharmacol 1987;21:153-63.

15. Sharma M, Kishore K, Gupta SK, et al. Cardioprotective potential of ocimum sanctum in isoproterenol induced myocardial infarction in rats. Mol Cell Biochem 2001;225:75-83.

16. Shetty S, Udupa S, Udupa L, Somayaji N. Wound healing activity of Ocimum sanctum Linn with supportive role of antioxidant enzymes. Indian J Physiol Pharmacol 2006;50:163-8.

17. Udupa SL, Shetty S, Udupa AL, Somayaji SN. Effect of Ocimum sanctum Linn. on normal and dexamethasone suppressed wound healing. Indian J Exp Biol 2006;44:49-54.

18. Mandal S, Das DN, De K, et al. Ocimum sanctum Linn—a study on gastric ulceration and gastric secretion in rats. Indian J Physiol Pharmacol 1993;37:91-2.

19. Seth SD, Johri N, Sundaram KR. Antispermatogenic effect of Ocimum sanctum. Indian J Exp Biol 1981;19:975-6.

20. Kasinathan S, Ramakrishnan S, Basu SL. Antifertility effect of Ocimum sanctum L. Indian J Exp Biol1972;10:23-5.

21. Brinker F. Herb Contraindications and Drug Interactions. Sandy, OR: Eclectic Medical Publications, 1998, 33-4.