Holy basil
Ocimum tenuiflorum, also called Ocimum sanctum, from the mint family
A leafy herb from India, also called tulsi, used in Ayurveda and taken as a tea or an extract. Studied mostly as a mouthwash or gel for the mouth and gums, and as an extract for stress. Here is every study in people we could find, sorted from each study's summary.
- Part used: leaf
- Most tested as a mouthwash or gel
- Mostly 1 to 9 weeks
From every paper to the studies that matter
Most research on holy basil is in the lab or about the plant's chemistry. Only a small share tests it in people, and that is what this page is about.
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1,073 papers mention holy basil. Every record in PubMed, all years
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48 are about people. The rest: 538 lab and animal studies, 79 reviews, 408 on chemistry, farming and more
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27 give holy basil on its own. 19 more test it inside a blend
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9 are randomised against a placebo. The strongest kind of study
Bar lengths use a square-root scale so the small numbers stay visible.
How much research there is
- 27 studies giving holy basil to people
- 9 of them randomised against a placebo
- 1,449 people taking part, where studies say
- 9 systematic reviews pooling the trials
Studies in people, by year published
Holy basil on its own.
What the studies looked at
Each study can measure several things. Choose a topic to see its studies in the list below.
Studies in people with a diagnosed condition are counted here and listed with their population. We describe what they measured, not what they might treat. Most studies also report safety; see below.
What was tested, and how much
Holy basil comes as dried leaf, extracts made in different ways, mouthwashes and gels, so milligrams don't compare well from one study to the next. Most mouthwash and gel studies don't give a daily amount.
Daily amount, one dot per study
Studies per extract
Named extracts are the maker's brand. "Not named" means the study didn't say.
All studies in people
Filter the list, then open a study on PubMed. Each row comes from the study's published summary.
| Study | Who took part | People | Extract and daily dose | Length |
|---|---|---|---|---|
| Anantam 2026RCT, active or other control | Adults having simple tooth extraction | 160 | Shyama Tulsi extract 4%On the skin | 1 weeks |
| Kamran 2023RCT, active or other control | Orthodontic patients with fixed appliances | 75 | Ocimum sanctum 4% mouthwashOn the skin | – |
| Nomura 2023RCT, placebo | Thyroid cancer patients during radioiodine therapy | 44 | Not named | 1 weeks |
| Deepika 2023Non-randomised controlled | Adults with periodontitis, pocket depth 5 mm | 40 | Ocimum sanctum 2% gelOn the skin | 35 weeks |
| Dalai 2023Non-randomised controlled | Adults with oral submucous fibrosis | 30 | Tulsi (compared with aloe vera)On the skin | 17 weeks |
| Lopresti 2022RCT, placebo | Adults aged 18-65 experiencing stress | 100 | Ocimum tenuiflorum extract (Holixer), 250 mg | 8 weeks |
| Jain 2022RCT, active or other control | Dental students | 80 | Not namedOn the skin | 2 weeks |
| Biswas 2022Single-arm or open-label | Patients with oral submucous fibrosis | 60 | Not namedOn the skin | 13 weeks |
| Deepika 2021Non-randomised controlled | Adults with gingivitis | 30 | Tulsi 2% gelOn the skin | 4 weeks |
| Rahalkar 2021RCT, active or other control | Adults with periodontal pockets, split-mouth | 15 | Not namedOn the skin | – |
| Nadar 2020RCT, placebo | School children aged 14-15 with gingivitis | 84 | Not namedOn the skin | 3 weeks |
| Penmetsa 2019RCT, active or other control | Adults with gingivitis | 60 | Not namedOn the skin | 4 weeks |
| Sharma 2019RCT, active or other control | Adults aged 17-35 with halitosis | 45 | Not namedOn the skin | 2 weeks |
| Megalaa 2018RCT, active or other control | Children at high caries risk | 60 | Not namedOn the skin | 1 weeks |
| Ahirwar 2018RCT, active or other control | Children with infected primary molars | 40 | Not namedOn the skin | 0 weeks |
| Satapathy 2017RCT, active or other control | Young overweight and obese adults | 30 | Not named, 500 mg | 8 weeks |
| Sultan 2016RCT, active or other control | Adolescents aged 15-17, crossover | 10 | Not named | – |
| Sampath 2015RCT, placebo | Healthy adult volunteers | – | EtOS, 300 mg | 4 weeks |
| Gupta 2014RCT, placebo | Healthy medical students | 108 | Ocimum sanctum mouthwashOn the skin | 4 weeks |
| Hosamane 2014RCT, placebo | Periodontally healthy volunteers | 30 | Not namedOn the skin | 1 weeks |
| Saxena 2012RCT, placebo | Adults with general stress symptoms | 150 | OciBest, 1,200 mg | 6 weeks |
| Ramesh 2012RCT, active or other control | Healthy volunteers | 60 | Not named | 1 weeks |
| Agarwal 2011RCT, active or other control | School children aged 14-15, crossover | 45 | Not namedOn the skin | 1 weeks |
| Mondal 2011Crossover, placebo | Healthy volunteers | 24 | Not named, 300 mg | 4 weeks |
| Bhattacharyya 2008Single-arm or open-label | Adults with generalized anxiety disorder | 35 | Not named, 1,000 mg | 9 weeks |
| Reshma 2005Non-randomised controlled | Oral cancer patients having radiotherapy, plus healthy controls | 34 | Ocimum flavonoids | 4 weeks |
| Agrawal 1996Crossover, placebo | Adults with type 2 diabetes | – | Not named | – |
What's known about safety
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In trials
No serious side effects were reported in a review of 24 studies of holy basil taken by mouth for 2 to 13 weeks. Nausea or diarrhoea can occur.
Jamshidi 2017, review of 24 studies; MSD Manual Professional, updated July 2025
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In the UK
The leaves and other parts above ground can be sold as food, as they were eaten in the EU before 1997. No UK registered herbal medicine contains it, and we found no official UK or EU upper limit.
EU Novel Food Status Catalogue; FSA novel foods guidance; MHRA list of traditional herbal registrations, Oct 2025
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Check first
Animal studies suggest it may affect fertility, so avoid it in pregnancy, when trying to conceive and when breastfeeding. Speak to a pharmacist or doctor first if you take blood thinners or thyroid medicine, or before surgery.
MSD Manual Professional, updated July 2025; Norwegian Institute of Public Health risk assessment, Nov 2023
Where these studies come from
We list every published study of holy basil in people. This first version is built from each study's summary; full-paper checks come next.
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We search
PubMed, the world's main library of medical research, for every paper on L-theanine.
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We keep studies in people
Lab and animal work is counted but left out of the list, because it doesn't tell you what happens in people.
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We note the basics
Who took part, how many, how much and for how long, from each study's published summary. A second check corrects what the first read gets wrong.
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We read them in full
Results appear once we've read the whole paper and checked every number. The date at the top shows when this entry was last updated.
Download the study list
Every study in people as a spreadsheet, 27 rows, free to reuse with a link back.
Versions
Each update to the data gets a new version number, so you can tell what changed and when.
See every version
1.0 · 19 Oct 2026. First release. Every published study giving holy basil on its own to people is listed from its summary. None is read in full yet.
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