What Is Holy Basil?

An Adaptogen Studied for Heart and Brain Health

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

Verywell / Anastasiia Tretiak​

Holy basil is commonly known as Tulasi in Sanskrit or Tulsi in Hindi. Holy basil is a perennial flowering plant from the mint family called Lamiaceae. While this plant is native to the Indian subcontinent, it may grow throughout Southeast Asia.

There are several different types of holy basil. The Ocimum tenuiflorum or Ocimum sanctum species consists of the following:

  • Rama or Sri tulsi, which has green leaves
  • Krishna or Shyama tulsi, which has purple-colored leaves

Another species of holy basil is called Ocimum gratissimum. This species or type of holy basil is also known as Vana or wild forest tulsi, which has dark green leaves.

In general, holy basil is thought to work by helping your body cope with various stressors—like emotional stress, an infection, or other medical conditions. This article will look at what the research shows about holy basil—how it's used, possible side effects, and interactions.

Dietary supplements are not regulated like drugs in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. Choose a supplement tested by a trusted third party, such as USP, ConsumerLabs, or NSF, when possible. However, even if supplements are third-party tested, that doesn't mean they are necessarily safe for all or effective in general. Therefore, it is essential to talk to your healthcare provider about any supplements you plan to take and check in about potential interactions with other supplements or medications.

Supplement Facts

  • Active ingredients(s): Eugenol, ursolic acid, beta-caryophyllene, linalool, and 1,8-cineole
  • Alternative name(s): Forest tulsi, Holy basil, Krishna tulsi, Ocimum gratissimum, Ocimum sanctum, Ocimum tenuiflorum, Rama tulsi, Shyama tulsi, Sri tulsi, Tulasi, Tulsi, Vana tulsi, wild tulsi
  • Legal status: Legal culinary (cooking) or over-the-counter (OTC) herb in most states (United States)
  • Suggested dose: Varies based on condition and dosage form
  • Safety considerations: Pregnancy, breastfeeding, and children. Use with blood pressure medications, blood thinners, relaxants, cholesterol-lowering, diabetes, and immune system medications.

Uses of Holy Basil

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

Like many herbs, people may use holy basil for various reasons. But there are several clinical trials assessing holy basil for the following potential uses. Read on for more information!

Metabolic Conditions

In a systematic review, several small short-term studies suggested holy basil improved metabolic conditions—like blood glucose (sugar) in diabetes, cholesterol in hyperlipidemia, blood pressure in hypertension, and body mass index (BMI). Metabolic conditions raise the risk of heart-related problems.

More study is needed to understand how holy basil impacts symptoms of these conditions.

Inflammation and the Immune System

In a systematic review, holy basil was linked to better lung function and relief of asthma symptoms in a small and short-term study—suggesting that holy basil may have lessened inflammation (swelling) in the airways.

The small short-term clinical trials suggested holy basil had some immune system (the body's defense system) effects—especially against viral infections.

Further study is needed.

Brain, Mood, and Stress Effects

In small, short-term studies (two weeks), holy basil did slightly better than a placebo (a substance with no medication) in improving attention and memory.

As for mood and stress, the results were mixed. This may have something to do with the various holy basil "dosage forms" used in each study—like capsules versus powder. Different parts of the holy basil plant were also used in each study.

Further studies are needed to understand how holy basil impacts symptoms of these conditions.

What Are the Side Effects of Holy Basil?

Similar to many medications, side effects are possible with holy basil.

Common Side Effects

A systematic review suggested holy basil has little to no side effects except for temporary, mild nausea.

Severe Side Effects

Several clinical trials suggested that holy basil isn't linked to serious side effects. But a severe allergic reaction is a possible serious side effect of any medication. Symptoms may include breathing difficulties, itchiness, and rash.

If you're having a severe allergic reaction or if any of your symptoms feel life-threatening, call 911 and get medical help right away.


Holy basil may pose risks in the following situations:

  • Severe allergic reaction: Avoid this herb if you have a severe allergic reaction to holy basil or any of its components (parts or ingredients).
  • Pregnancy or breastfeeding: Studies with holy basil may exclude pregnant or breastfeeding people. As a result, information is likely limited on the safety and effectiveness of holy basil while pregnant or breastfeeding. Data on the safety and effects of holy basil in nursing infants is also limited. For this reason, take holy basil with caution. Your healthcare provider can help you weigh the benefits and risks of taking holy basil during pregnancy or breastfeeding.
  • Children: A 2017 systematic review didn't include studies with children. There is limited information about the effects and safety of holy basil in children. Reach out to your child's healthcare provider (pediatrician) to discuss the benefits and risks of holy basil.
  • Older adults: Older adults did participate in some studies included in a systematic review of holy basil. While holy basil didn't appear to be linked to severe side effects, these studies were small and short-term. Older adults may be more sensitive to side effects from medications.

Dosage: How Much Holy Basil Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.

While there are several small short-term studies on holy basil, larger, well-designed studies are needed. For this reason, there are no guidelines on the appropriate dosage to take for any condition.

If you take holy basil, follow your healthcare provider's suggestions and product label instructions.

What Happens If I Take Too Much Holy Basil?

There is little information about holy basil toxicity and overdoses in humans. But there were negative effects on sperm count and sex hormones in male rabbits with high doses of holy basil leaves at two grams for 30 days.

If you think you're experiencing an overdose or life-threatening symptoms, get medical help immediately.


Use caution when taking holy basil with the following:

  • Blood pressure medications: Holy basil demonstrated blood pressure-lowering effects. This may have additive effects with antihypertensives—like Microzide (hydrochlorothiazide). If your blood pressure is too low, you may experience dizziness and feel faint.
  • Blood thinners: In animal studies, holy basil slowed blood clotting time. Since your body will take longer to stop the bleeding, you may also bleed longer. This means that holy basil may interact with other blood thinners, such as Coumadin (warfarin).
  • Cholesterol medications: Holy basil demonstrated cholesterol-lowering effects. This may have additive effects or increase the side effects of your cholesterol-lowering medications, such as Lipitor (atorvastatin).
  • Diabetes medications: Holy basil has blood sugar-lowering effects. This may have additive effects with your diabetes medications. If your blood sugar is too low, symptoms may include excessive tiredness and sweating.
  • Immune support medications: Since holy basil demonstrated immune system effects, use caution with other similar medications, such as Humira (adalimumab). Humira is used for autoimmune conditions, where your body attacks parts of your body by mistake.
  • Relaxants: After taking holy basil, you might experience a calming effect. This might increase the side effects of other medications that have similar effects, such as sleep-inducing medications—like Ambien (zolpidem).

It is essential to carefully read a supplement's ingredient list and nutrition facts panel to know which ingredients and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications. 

Dried holy basil
Verywell / Anastasia Tretiak 

How to Store Holy Basil

Storage instructions vary for different products. Carefully read the directions and packaging label on the container. Keep your medications tightly closed and out of the reach of children and pets, ideally locked in a cabinet or closet. Try to store your medicines in a cool and dry place.

Discard after one year or as indicated on the packaging. Avoid pouring unused and expired products down the drain or in the toilet. Visit the FDA's website to know where and how to discard all unused and expired medications. You can also find disposal boxes in your area.

Ask your healthcare provider if you have any questions about the best ways to dispose of your medications or supplements.

If you plan to travel with holy basil, get familiar with your final destination's regulations. Checking with the U.S. embassy or consulate might be a helpful resource.

Similar Supplements

It isn't exactly clear exactly how holy basil works. While more research is needed, it's believed that some of holy basil's effects may involve the gamma-aminobutyric acid (GABA) pathways that naturally exist in your body.

While GABA supplements exist, they do not readily cross the blood-brain barrier in this form. With this in mind, they're likely not as effective as some companies would lead you to believe.

Supplements with proven relaxant effects include valerian, magnesium, and melatonin.

Holy basil has demonstrated blood sugar- and cholesterol-lowering effects. Holy basil may also have effects on immune and memory support. There are multiple herbs and supplements with these effects. Speak with your healthcare provider or pharmacist for questions.

In addition to being an over-the-counter (OTC) supplement, holy basil is available from natural sources. Holy basil can be used as a culinary (cooking) herb.

Frequently Asked Questions

  • What is the most common dossage form for holy basil?

    Holy basil is available in many dosage forms—with tea or infusion bags likely being the most common.

  • Is holy basil available from manufacturers in the United States?

    Yes. There are holy basil products that are made by manufacturers in the United States.

  • Does holy basil have any nutritional benefits?

    Yes. Holy basil has several nutrients, including vitamin C, calcium, iron, and zinc.

  • How do I take holy basil safely?

    In general, to take herbal medications—like holy basil—safely, inform your healthcare providers and pharmacists about any medication changes. This includes over-the-counter (OTC), herbal, natural medications, and supplements.

    They can help prevent possible interactions and side effects. They can also make sure that you’re giving holy basil a good trial at appropriate doses.

Sources of Holy Basil & What to Look For

There are several different sources of holy basil.

Food Sources of Holy Basil

Holy basil is naturally available as a plant from the mint family. It's commonly used as a culinary (cooking) herb.

In general, dietary changes may interact with your medications or affect your medical conditions. For this reason, talk with your healthcare provider first. They will help you safely make any dietary changes.

Holy Basil Supplements

Holy basil is available in many dosage forms, including capsules and tablets. If you have difficulties swallowing pills, holy basil is available in other dosage forms:

  • Liquid
  • Powder
  • Tea bags

Holy basil is also available as vegetarian and vegan products. The specific product you choose will depend on your preference and what you hope to get in terms of effects. Each product may work differently depending on the form, so following the directions is essential.


Holy basil is a perennial flowering plant from the mint family. While it's commonly used as a culinary (cooking) herb, it may also have some potential medicinal effects. For example, it may reduce blood pressure, blood sugar, and cholesterol. What's more, it might have some effects on memory and immune support.

Although holy basil is available as a cooking herb and an over-the-counter (OTC) supplement, side effects and drug interactions are possible. More research is still needed to assess holy basil's effectiveness and safety. Before using holy basil, talk with your pharmacist or healthcare provider to help you safely achieve your health goals.

11 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.
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  2. Petruzello M. Holy basil. Encyclopædia Brittanica.

  3. 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

  4. National Heart, Lung and Blood Institute. What is metabolic syndrome?.

  5. Lopresti AL, Smith SJ, Metse AP, et al. A randomized, double-blind, placebo-controlled trial investigating the effects of an Ocimum tenuiflorum (holy basil) extract (Holixer) on stress, mood, and sleep in adults experiencing stress. Frontiers in Nutrition. 2022;9:965130. doi: 10.3389/fnut.2022.965130

  6. Association for the Advancement of Restorative Medicine. Holy basil, Tulsi (Ocimum sanctum).

  7. Narayana DBA, Manohar R, Mahapatra A, et al. Posological conditions of Ocimum sanctum (Tulasi) as per Ayurvedic science and pharmacuetical sciences. Indian J Pharm Sci. 2014;76(3):240-245.

  8. Singh S, Rehan HMS, Majumdar DK. Effect of Ocimum sanctum fixed oil on blood pressure, blood clotting time, and pentobarbitone-induced sleeping time. Journal of Ethnopharmacology. 2001;78(2-3):139-143. doi: 10.1016/S0378-8741(01)00336-1

  9. National Institutes of Health Office of Dietary Supplements. Dietary supplement label database.

  10. Mederi Center. Holy basil: an herb with incomparable benefits.

  11. MedlinePlus. A guide to herbal remedies.

By Ross Phan, PharmD, BCACP, BCGP, BCPS
Ross is a writer for Verywell with years of experience practicing pharmacy in various settings. She is also a board-certified clinical pharmacist and the founder of Off Script Consults.

Originally written by Sherry Christiansen
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.
Learn about our editorial process