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Holy Basil


Laura Shane-McWhorter

, PharmD, University of Utah College of Pharmacy

Reviewed/Revised Jan 2022 | Modified Sep 2022

What is holy basil?

The scientific name of holy basil is Ocimum tenuiflorum.

  • The Hindu name for holy basil is tulsi, which means the incomparable one.

  • Other names for this plant are Thai basil and brush-leaf tea.

  • Holy basil is a plant that is native to India but also grows in Australia, West Africa, and some Middle Eastern countries.

  • This herb has been used for more than 3,000 years as part of Ayurvedic medicine in India.

  • Hindus view holy basil as a sacred plant, and they often plant it around Hindu shrines.

  • Medicine is made from the leaves, stems, and seeds of holy basil plants.

  • Some people use holy basil in cooking (and it is sometimes called "hot basil" in cookbooks) because of its bitter, spicy taste.

  • Holy basil is available in dietary supplements in the form of pills and capsules, and its essential oil is distilled from the plant's leaves and flowers.

What claims are made about holy basil?

Advocates believe that holy basil is an adaptogen Adaptogens "Adaptogen" is a term for certain foods and supplements that are said to help the body cope with "stress." Stress may be psychologic (in the mind), but also may be physical (in the body), and... read more . This herbal medicine term means that this substance is thought to help the body respond to stress and restore normal function. Other uses of holy basil are to:

  • Reduce anxiety and stress

  • Lower blood sugar in people with diabetes

  • Lower cholesterol levels

  • Provide protection from bacterial and viral infections

  • Promote wound healing

  • Reduce inflammation

Does holy basil work?

Any single compound, including holy basil, is highly unlikely to have such a broad range of health benefits. Thus, evidence is very unlikely to confirm such multiple benefits.

Studies in animals suggest that holy basil seed oil might do the following:

  • Prevent ulcers and changes in the heart and blood vessels due to stress

  • Slow the growth of cancer cells and lengthen survival in animals with cancer

  • Reduce anxiety

  • Reduce plaque and gingivitis in the mouth when taken as a leaf extract in a mouthwash

But none of these findings has been replicated in people.

The evidence from studies in people to show that holy basil has health benefits is limited. Many of these studies are small and of poor quality. These studies show that holy basil could have the following health benefits, among others, but larger studies with better designs are needed to confirm these preliminary findings:

  • Reduce anxiety and relieve the stress and depression that accompany anxiety

  • Decrease blood sugar levels

  • Decrease symptoms of stress (for example, sleep problems, exhaustion, forgetfulness)

  • Improve breathing function and reduce attacks in people with asthma

  • Improve the immune system's response to viral infections

  • Reduce inflammation and joint pain

What are the possible side effects of holy basil?

Holy basil seems to be safe for most people when taken by mouth for up to 8 weeks. But holy basil can have side effects, such as nausea or diarrhea.

What drug interactions occur with holy basil?

Because holy basil might slow down the blood's ability to form clots, taking both holy basil and drugs that slow blood clotting (for example, aspirin, clopidogrel, dalteparin, heparin, and warfarin) could increase the likelihood of bruising and bleeding. In animal studies, holy basil may increase the effect of certain sedatives.

Holy basil may lower blood sugar and thus possibly result in hypoglycemia Hypoglycemia Hypoglycemia is abnormally low levels of sugar (glucose) in the blood. Hypoglycemia is most often caused by medications taken to control diabetes. Much less common causes of hypoglycemia include... read more when combined with some antihyperglycemic (glucose-lowering) drugs such as insulin or sulfonylureas (such as glimepiride).


Holy basil is not recommended because the claimed health effects have not been confirmed in high-quality studies in people.

Holy basil is probably safe for most people; however,

  • Pregnant and breastfeeding women, women who are trying to become pregnant, and people with type 2 diabetes, hypothyroidism, and those undergoing surgery should avoid holy basil.

  • People who take certain drugs (including drugs to slow blood clotting or decrease blood sugar) should talk to their doctor before taking holy basil.

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