Herb & supplement monograph

Holy Basil Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Holy Basil interacts with medications. The heart of this page is the interaction list — every drug Holy Basil is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Holy Basil is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

Check Holy Basil against your medication

Add one medication

✓ Supplement

Holy Basil

1 Your medication

Start typing any prescription or over-the-counter drug name.

Reviewed by licensed pharmacists Sourced from Natural Medicines

On this page

Holy Basil Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Holy Basil drug interaction appears low for most people, though it is worth extra care with certain closely monitored medicines. None of the listed interactions are rated major, and nearly all rest on animal or lab findings rather than confirmed effects in people.

Interactions deserving the most attention

The best-supported concern involves diabetes medications. Small human studies show holy basil can lower blood sugar in people with type 2 diabetes, so adding it could push blood sugar too low in someone whose treatment is finely tuned. Animal research also suggests holy basil seed oil might slow clotting, so people taking anticoagulant or antiplatelet drugs should watch for unusual bruising or bleeding. A similar animal-only signal suggests the seed oil could add to the sedative effect of pentobarbital.

What the rest of the list means

The long list of interacting medications should not be read as a long list of dangers. Most entries come from the same few concerns, predicted from animal or lab research on how holy basil might affect bleeding, blood sugar, or sedation. For most of these combinations, no meaningful problem has been shown in people.

Check your medications against Holy Basil

Based on HelloPharmacist’s Holy Basil interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Holy Basil

212 medications have a known interaction with Holy Basil, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Holy Basil using our pharmacist-reviewed interaction data.

AI summaries are generated from our Holy Basil interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Holy Basil combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Holy Basil affects

Every type of medication (drug category) Holy Basil is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 3 drug categories Holy Basil interacts with

Anticoagulant/antiplatelet DrugsAntidiabetes DrugsPentobarbital (nembutal)

Anticoagulant/Antiplatelet Drugs

Theoretically, holy basil seed oil might increase the risk of bleeding when used with anticoagulant or antiplatelet drugs.
Animal research shows that holy basil seed oil can prolong bleeding time, possibly due to inhibition of platelet aggregation. However, it is not known if this occurs in humans.

Likelihood Possible Evidence D

Antidiabetes Drugs

Theoretically, holy basil might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Small clinical studies show that taking holy basil can decrease fasting blood glucose and other measures of glycemic control in patients with type 2 diabetes.

Likelihood Possible Evidence B

Pentobarbital (Nembutal)

Theoretically, holy basil seed oil might increase the sedative effects of pentobarbital.
Animal research shows that holy basil seed oil increases pentobarbitone-induced sleeping time. However, it is not known if this occurs in humans or if this applies to other barbiturates or sedatives.

Likelihood Possible Evidence D

Monograph

Holy Basil: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Holy basil (tulsi) is a traditional Ayurvedic herb most often used today for stress and general wellness, but the human evidence is mostly small and preliminary. It is generally well tolerated by most adults, but it should be avoided in pregnancy and used cautiously by anyone with health conditions or taking medications. Talk to your pharmacist or doctor before starting it.

Scientific name: Ocimum tenuiflorum
Family: Lamiaceae
Part used: Leaves, seeds, and essential oil
Common forms: Tea, capsules, tablets, powder, liquid extract, essential oil

People commonly use it for

Stress and anxiety
Blood sugar support
Respiratory complaints
General immune and wellness support
Inflammation

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Generally well tolerated short-term in adults, but high-quality long-term safety data are limited.

PregnancyPossibly Unsafe

When used in high doses during pregnancy or when trying to conceive. Animal research suggests that relatively high doses of holy basil extract (200 mg...

Read the full pregnancy detail

BreastfeedingPossibly Unsafe

When used in high doses during pregnancy or when trying to conceive. Animal research suggests that relatively high doses of holy basil extract (200 mg...

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Holy basil, often called tulsi, is a fragrant herb that has been used in Ayurvedic medicine in India for hundreds of years. In Hindi, tulsi means "the incomparable one," and the plant is considered sacred in many Hindu traditions. It is a leafy plant in the mint family, with small green or purplish leaves and a slightly bitter, spicy, clove-like aroma.

Holy basil grows widely in India and other warm parts of Asia. People use it as a tea, in capsules or tablets, as a powdered leaf, as a liquid extract, and as an essential oil.

It is worth noting that holy basil is different from the common culinary basil used in cooking. They belong to the same plant family but are distinct plants with different flavors and traditional uses.

How it works

Holy basil contains several plant compounds that may be biologically active, including eugenol, ursolic acid, rosmarinic acid, and various antioxidants. Researchers think these may have antioxidant and anti-inflammatory effects.

It is sometimes described as an adaptogen, meaning it is thought to help the body handle stress. Some lab and animal studies suggest it may affect stress hormones, blood sugar, and inflammation pathways.

Keep in mind that most of this information comes from laboratory and animal research. How these effects translate to people taking holy basil is still not well understood.

Effectiveness

Does Holy Basil work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 20 uses evaluated

20 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

For Holy Basil, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 20 conditions — evidence insufficient to rate

Insufficient Reliable Evidence To Rate Age-related cognitive decline