What Is Holy Basil?

An Anti-Aging Adaptogen That Protects the Heart and Brain

Holy basil tea, dried herbs, essential oil, tincture, and soft gels

Verywell / Anastasiia Tretiak​

Holy basil (Ocimum tenuiflorum), known in Hindi as tulsi, is a medicinal herb used to combat stress and help address high blood sugar, inflammation, arthritis, and more. Medicinal preparations are made from holy basil's leaves, stems, and seeds of the plant.

Holy Basil has violet flowers and blossoms. The green stems sometimes have a purple tinge. The plant is often used in Thai food. It's much spicier than other types of basil and is sometimes called "hot basil."

This article will look at how it's used, what research shows, the possible side effects, what to look for when buying, and how to prepare and store holy basil.

Other names for holy basil:

  • Albahaca santa
  • Bai kaprow
  • Baranda
  • Basilic indien/Indian basil
  • Basilic sacré/basilic sacré pourpre/basilic saint
  • Green holy basil/red holy basil/sacred basil
  • Kala tulsi
  • Krishna tulasi/Krishna tulsi
  • Manjari
  • Ocimum sanctum
  • Rama tulsi
  • Tulasi

Health Benefits

Hindu people worship holy basil. It's considered the "Mother Medicine of Nature." It’s been revered since ancient times as an herb that can promote a healthy body, mind, and spirit.

The sacred plant is often planted around Hindu shrines. The name tulsi means "the incomparable one."

In Western medicine, holy basil is valued as an adaptogen. That's something that helps your body adapt to stress. The plant has been used to:

  • Combat negative effects of stress
  • Stabilize blood sugar levels
  • Promote longevity

Studies show holy basil has a wide range of health-promoting properties. It's an:

  • Adaptogenic
  • Anti-arthritic
  • Anti-coagulant
  • Anti-diabetic
  • Anti-inflammatory
  • Anti-pyretic (prevents fever)
  • Antidiarrheal
  • Antimicrobial (including antibacterial, antiviral, antifungal, and more)
  • Antioxidant
  • Antitussive (treats cough)
  • Liver-, brain-, and heart-protectant

A 2017 review of research suggests holy basil may help "address the psychological, physiological, immunological, and metabolic stresses of modern living."

What Are Adaptogens?

Adaptogens are plant substances that help your body deal with stress. Adaptogens may:

  • Balance stress hormones, such as cortisol
  • Improve brain function
  • Boost the immune system
  • Lower inflammation
  • Improve energy levels
  • Improve the function of organs and systems
  • Slow aging


Traditional Uses

Holy basil is used for its many health benefits and is popular in Indian Ayurvedic medicine. Even though research hasn't yet proven its effectiveness, it's used for a long list of conditions.

Infectious conditions:

Gastrointestinal problems:

Other conditions/symptoms:

  • Asthma
  • Anxiety
  • Back pain
  • Diabetes
  • Heart disease
  • Genitourinary disorders (conditions involving the urinary system and genitals)
  • Headache
  • Stress

It's also used to treat snakebites and ringworm and as a mosquito repellant. 

Modern Research

Modern science has gathered evidence supporting some of holy basil's traditional uses. In a 2017 review of clinical studies on holy basil, it was found to "provide favorable clinical effects" for: 

  • Immunity and infections
  • Inflammation
  • Metabolic disorders, including diabetes
  • Neurocognitive disorders, including Alzheimer’s disease and depression
  • Other chronic diseases

More research needs to confirm the findings before anyone can say for certain that holy basil is safe and effective for any particular condition.

How It Works

Holy basil has a complex makeup of phytochemicals (plant substances). Researchers have found its leaves contain several bioactive (medicinal) compounds, including:

  • Eugenol (clove oil): May lower blood glucose levels, treat digestive and respiratory problems
  • Ursolic acid: Antioxidant, anti-inflammatory, antibacterial, anticancer, antifungal properties
  • ß-caryophyllene: Anti-inflammatory, analgesic (painkiller), antipyretic
  • Linalool: Insecticide (kills insects)
  • 1,8-Cineole (eucalyptol): Cough, allergies, and asthma relief, immune support, anti-inflammatory, anti-leukemia cells

Recap

Holy basil is a highly valued medicinal herb. It's often used in Thai food. Research shows that it's an adaptogen, which means it helps your body deal with stress. It may also be used to treat many conditions, including diabetes, the common cold, and fever.

Traditional uses are many and preliminary research has begun to back some of them. The plant has a complex makeup including several chemicals believed to be medicinal.

Possible Side Effects

In the 2017 review, the only specific side effect reported was mild nausea that went away with continued use. All of the reviewed studies reported either no side effects or mild ones.

However, the longest study was only 13 weeks long. So the possible long-term side effects are unknown.

Special Precautions

Holy basil may pose risks in some situations.

  • Pregnancy: Avoid holy basil if you're trying to conceive. Preliminary animal studies show it may cause uterine contractions and impair fertility. Holy basil's safety during pregnancy or breastfeeding isn't established.
  • Blood clotting: Holy basil may slow blood clotting. Don't take it for two weeks before or after surgery.

Contraindications

Holy basil isn't recommended if you're taking anticoagulants (blood thinners) such as:

Holy basil can cause relaxation. Don't use it on top of drugs that cause drowsiness.

Talk to your healthcare provider or pharmacist before taking holy basil with prescription drugs, over-the-counter medicine, or supplements.

Recap

In studies, side effects have been mild and few. Longer-term studies are needed to fill out holy basil's safety profile. Avoid holy basil if you're trying to get pregnant or if you're pregnant or breastfeeding. Don't take it if you're on blood thinners. Don't combine it with other drugs that cause drowsiness.

Dried holy basil
Verywell / Anastasia Tretiak 

Selection, Preparation, and Storage

Unlike prescription drugs, herbal supplements aren't regulated by the U.S. Food and Drug Administration (FDA). It’s not always easy to identify which products are potent and pure.

Choose a product that's certified organic, ethically wild-harvested, all-natural, and certified by a third-party organization such as:

  • U.S. Pharmacopeia
  • NSF International
  • ConsumerLab.com 

These organizations evaluate and report on a product’s safety, purity, and potency.

Preparation

Holy basil leaves are often made into tea for medicinal use. But according to traditional Ayurvedic medicine, using the whole plant ensures you get all of the bioactive chemicals.

  • Make tea by brewing 2 to 3 teaspoons of dried holy basil in boiling water. Steep for 5 or 6 minutes. Drink it at bedtime to get the relaxing effects.
  • To make an essential oil, distill the plant's leaves and flowers.
  • Or you can cook with. It's common in Asian dishes. The taste is spicy and bitter.

You can also get it as a supplement. It comes in pill form or as a liquid extract.

Dosage

A safe long-term dosage of holy basil has not been well established. Various dosages have been used in short-term studies.

  • 500 milligrams (mg) of left extract twice a day reduced anxiety and depression. 
  • 300 mg per day of leaf extract for 30 days eased central nervous system disorders.
  • 400 mg of extract in the morning and 800 mg at night for six weeks decreased stress symptoms including sleep and memory problems, severe fatigue, and sexual dysfunction.

Storage

If you grow your own holy basil, you can harvest the stems and leaves before the flower appears. Dry the sprigs by hanging them upside-down in a dark, cool area for two weeks.

Store the dried herb in a glass jar with an airtight lid. Keep the jar in a cool, dark place and use the holy basil within one year.

Purchased tinctures, dried herbs, and supplement pills should be stored according to the manufacturer's instructions.

Summary

Holy basil is an adaptogen, anti-inflammatory, antioxidant, and more. It may be beneficial for many conditions. Research is in its early stages but it's starting to support some of the traditional uses.

Side effects may include mild, transient nausea. Some studies reported no side effects. However, longer-term studies need to be done.

It's best not to take holy basil if you're trying to conceive or currently pregnant or breastfeeding. Don't combine it with blood thinners or other drugs that cause drowsiness.

Choose holy basil products that are organic and certified by a third-party lab. You can make it into tea or essential oils. It's available in supplement form as well.

Dosages aren't established. Studies have used between 300 mg per day and 1200 mg a day (in doses of 400 and 800.)

A Word From Verywell

Holy basil appears promising. Still, not enough long-term, quality studies have been done. Its safety and effectiveness still need to be proven.

If you want to try it, talk to your healthcare provider, buy from a reputable source, and take it as directed.

Frequently Asked Questions

  • Is there a difference between holy basil and the usual basil used in cooking?

    Yes, they are different. Basil comes in about 150 different varieties. Each has its own unique healing properties, flavor, smell, and culinary uses.


  • Is holy basil safe for children?

    This is unknown. The safety of holy basil for children and infants isn't established by clinical studies.

  • Can holy basil lower blood pressure?

    Preliminary studies show holy basil normalizes blood sugar, blood pressure, and lipid (cholesterol) levels. Even so, don't replace any prescription medication with holy basil (or any other supplement) without talking to your healthcare provider.

  • Does holy basil have any nutritional benefits?

    Yes, holy basil has many nutrients including vitamins like vitamin A and minerals such as calcium, iron, and zinc.

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Cohen MM. Tulsi - Ocimum sanctum: a herb for all reasons. J Ayurveda Integr Med. 2014;5(4):251-259. doi:10.4103/0975-9476.146554

  2. 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;2017:9217567. doi:10.1155/2017/9217567

  3. National Institute of Diabetes and Digestive and Kidney Diseases & National Library of Medicine: LiverTox. Eugenol (clove oil).

  4. Seo DY, Lee SR, Heo JW, et al. Ursolic acid in health and diseaseKorean J Physiol Pharmacol. 2018;22(3):235-248. doi:10.4196/kjpp.2018.22.3.235

  5. National Institutes of Health, National Library of Medicine, National Center for Biotechnology Information: PubChem. beta-Caryophyllene.

  6. National Institutes of Health, National Library of Medicine, National Center for Biotechnology Information: PubChem. Linalool.

  7. National Institutes of Health, National Library of Medicine, National Center for Biotechnology Information: PubChem. Eucalyptol.

  8. RX List. Holy basil.

  9. Drugs.com. Holy basil.

  10. Iowa State University Extension and Outreach. Basil. Iowa State University, Horticulture and Home Pest News.

By Sherry Christiansen
Sherry Christiansen is a medical writer with a healthcare background. She has worked in the hospital setting and collaborated on Alzheimer's research.