--- title: "Holy Basil: Benefits, Uses & Side Effects | Herbadex" description: "Holy basil (tulsi) showed possible benefits for stress and blood sugar in small, low-quality studies. Take care with blood thinners and diabetes medicines." language: en url: https://herbadex.com/en/herb/holy-basil/ source: Herbadex (https://herbadex.com) --- [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) # Holy Basil Ocimum tenuiflorum B Limited clinical evidence Holy basil (tulsi) showed possible benefits for stress and blood sugar in small, low-quality studies. Take care with blood thinners and diabetes medicines. [Sleep, Stress & Mood](https://herbadex.com/en/for/sleep-stress/) [Metabolism, Weight & Blood Sugar](https://herbadex.com/en/for/metabolism/) ![](/illustrations/kuru-bitki.svg)H Holy Basil Pregnancy **⚠ Avoid** Breastfeeding **⚠ Avoid** Children **Unknown** Drug interactions **Interaction reported** ## At a glance Holy basil (tulsi, Ocimum tenuiflorum) is a basil species used in Ayurveda as an adaptogen to help the body cope with stress. Small human studies suggest possible effects on anxiety, stress and blood sugar, but there are no high-quality studies. It is different from culinary basil (O. basilicum). **Parts used:** leaves **Key constituents:** Eugenol, Ursolic acid, Rosmarinic acid Updated: October 24, 2026 Sources and research limitations appear below. The existence of a source does not mean every use has been clinically verified. ## What is it used for? - B Limited clinical evidence Small, lower-quality human studies suggest a possible benefit for anxiety and stress symptoms. No high-quality studies confirm this; a systematic review of 24 clinical studies also calls for larger, well-designed trials. \[1\] \[2\] - B Limited clinical evidence Small human studies found lower blood sugar; the studies were small and of limited quality. For this reason, blood sugar may fall too much in people taking diabetes medicine. \[1\] \[2\] ## How is it used? ### Tea The leaf is taken by mouth as a tea or supplement. Oral use has been studied for up to 8 weeks; safety of longer use is unknown and there is no verified dose. **Duration limit:** 8 weeks \[1\] ## Safety & interactions Duration limit: 56 days - Do not use in pregnancy, while breastfeeding or when trying to conceive; high doses reduced successful pregnancy in animals. - It may slow blood clotting; do not use it before surgery and tell your doctor. - It may lower thyroxine levels; people with an underactive thyroid (hypothyroidism) should not use it. - People with type 2 diabetes or taking diabetes medicine should not use it without asking a doctor. - Safety beyond 8 weeks of use has not been studied. \[1\] \[2\] ### Drug interactions | Medicine / substance | Effect | Severity | | --- | --- | --- | | Blood thinners and antiplatelet drugs (warfarin, heparin, aspirin, clopidogrel) | May increase bruising and bleeding by slowing clotting. Ask your doctor before combining. [1] | Moderate | | Insulin and sulfonylureas (e.g. glimepiride) | Because it may lower blood sugar, combining them could cause hypoglycaemia. [1] | Moderate | | Sedatives | Increased the effect of some sedatives in animal studies; relevance in humans is unknown. [1] | Minor | ### Side effects - Nausea - Diarrhoea #### ⚕ When to see a doctor - If high fever, shortness of breath or purulent/bloody phlegm develops - If symptoms do not improve within 1–2 weeks or worsen - If severe abdominal pain, jaundice, rash or allergic reaction occurs ## Frequently asked questions Does tulsi tea help with stress? Small, lower-quality studies suggest a possible benefit for anxiety and stress symptoms. Without high-quality studies, the effect is not proven. Is holy basil the same as regular basil? No. Holy basil is Ocimum tenuiflorum (O. sanctum), while culinary basil is Ocimum basilicum. Tulsi studies cannot be applied to culinary basil. Does tulsi lower blood sugar? Small studies found lower blood sugar. If you take diabetes medicine, ask your doctor, as your blood sugar could fall too much. Can I use tulsi while pregnant? No. It should not be used in pregnancy, while breastfeeding or when trying to conceive; high doses harmed pregnancy in animal studies. Does tulsi affect the thyroid? It may lower thyroxine levels and worsen hypothyroidism. Ask your doctor before using it if you have thyroid disease. ## Sources Source type is not an efficacy rating. A monograph may document traditional use or safety. Claim numbers link to the relevant source; the access date does not indicate professional approval. 1. [Holy Basil](https://www.merckmanuals.com/home/special-subjects/dietary-supplements-and-vitamins/holy-basil) MSD Manual Consumer Version (Merck & Co.) · 2025 · Reference book Source accessed: October 24, 2026 2. [The Clinical Efficacy and Safety of Tulsi in Humans: A Systematic Review of the Literature](https://doi.org/10.1155/2017/9217567) Evidence-Based Complementary and Alternative Medicine · 2017 · Systematic review Source accessed: October 24, 2026 ### Cite This Page Holy Basil (Ocimum tenuiflorum). Herbadex — Doğal Şifa Rehberi (2026). https://herbadex.com/en/herb/holy-basil/ ## Related guides and comparisons - [Herbal Products and Drug Interactions](https://herbadex.com/en/guide/herb-drug-interactions/) - [Herbal Products in Pregnancy and Breastfeeding](https://herbadex.com/en/guide/herbal-products-in-pregnancy/) ## On this page At a glance What is it used for? How is it used? Safety & interactions Frequently asked questions Sources Related herbs ## Related herbs ### [St. John's Wort](https://herbadex.com/en/herb/st-johns-wort/) A Strong clinical evidence Hypericum perforatum St John's wort extract may help with mild to moderate depressive episodes, but it seriously interacts with many medicines, including the pill. [Sleep, Stress & Mood](https://herbadex.com/en/for/sleep-stress/) [Digestion](https://herbadex.com/en/for/digestion/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [Ashwagandha](https://herbadex.com/en/herb/ashwagandha/) B Limited clinical evidence Withania somnifera (L.) Dunal Ashwagandha root extracts have limited evidence for stress and sleep. Avoid in pregnancy, breastfeeding and liver disease; drug interactions are possible. [Sleep, Stress & Mood](https://herbadex.com/en/for/sleep-stress/) [Men’s Health](https://herbadex.com/en/for/mens-health/) [Clay, Soap & Other](https://herbadex.com/en/form/other/) ### [Hawthorn](https://herbadex.com/en/herb/hawthorn/) B Limited clinical evidence Crataegus spp. Hawthorn leaf and flower are traditionally used for palpitations linked to mild anxiety, after a doctor has ruled out serious heart disease. [Heart & Circulation](https://herbadex.com/en/for/heart-circulation/) [Sleep, Stress & Mood](https://herbadex.com/en/for/sleep-stress/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [Lavender](https://herbadex.com/en/herb/lavender/) B Limited clinical evidence Lavandula angustifolia Lavender flower tea is traditionally used to relieve mild symptoms of stress and exhaustion and to aid sleep in adults and teenagers. [Sleep, Stress & Mood](https://herbadex.com/en/for/sleep-stress/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [Lemon Balm](https://herbadex.com/en/herb/lemon-balm/) B Limited clinical evidence Melissa officinalis Lemon balm leaf tea is traditionally used to relieve mild symptoms of stress, to aid sleep and for mild bloating and wind in adults. [Sleep, Stress & Mood](https://herbadex.com/en/for/sleep-stress/) [Digestion](https://herbadex.com/en/for/digestion/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [Passion Flower](https://herbadex.com/en/herb/passion-flower/) B Limited clinical evidence Passiflora incarnata Passion flower (Passiflora incarnata) herb tea is traditionally used to relieve mild symptoms of stress and to aid sleep. [Sleep, Stress & Mood](https://herbadex.com/en/for/sleep-stress/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ## Other herbs in the same preparation form (Dried Herb & Tea) [Dried Herb & Tea →](https://herbadex.com/en/form/dried-herb-tea/) ### [Psyllium Husk](https://herbadex.com/en/herb/psyllium-husk/) A Strong clinical evidence Plantago ovata Taken with plenty of water, psyllium husk helps soften stools in constipation; keep a gap between it and other medicines. [Digestion](https://herbadex.com/en/for/digestion/) [Heart & Circulation](https://herbadex.com/en/for/heart-circulation/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [Black Tea](https://herbadex.com/en/herb/black-tea/) A Strong clinical evidence Camellia sinensis Its caffeine can increase attention and alertness. Observational studies link regular tea drinking to lower cardiovascular risk. [Energy & Focus](https://herbadex.com/en/for/energy-focus/) [Heart & Circulation](https://herbadex.com/en/for/heart-circulation/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [Artichoke Leaf](https://herbadex.com/en/herb/artichoke-leaf/) B Limited clinical evidence Cynara cardunculus (syn. C. scolymus) Artichoke leaf is traditionally used for indigestion with fullness, bloating and wind; it must not be used with gallbladder disease. [Digestion](https://herbadex.com/en/for/digestion/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) ### [Black Elderberry Fruit](https://herbadex.com/en/herb/black-elderberry-fruit/) B Limited clinical evidence Sambucus nigra L. Black elderberry is an anthocyanin-rich fruit studied for cold symptoms, but clinical evidence is limited. Raw or unripe berries should not be eaten. [Respiratory, Throat & Mouth](https://herbadex.com/en/for/respiratory/) [Dried Herb & Tea](https://herbadex.com/en/form/dried-herb-tea/) This page is for information only and is not medical advice. If you take medication, are pregnant, or have a health condition, talk to your doctor or pharmacist before use.