Drug & supplement interaction

Basil + Bisoprolol, Hydrochlorothiazide

Bisoprolol, Hydrochlorothiazide brand name: Ziac.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Basil has a moderate interaction with Bisoprolol, Hydrochlorothiazide. Theoretically, basil might increase the risk of hypotension when taken with antihypertensive drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Basil and Bisoprolol, Hydrochlorothiazide

Here is the interaction we found between these two, with the evidence behind it.

Moderate

ANTIHYPERTENSIVE DRUGS

Why this applies to Bisoprolol, Hydrochlorothiazide

Bisoprolol, Hydrochlorothiazide falls under ANTIHYPERTENSIVE DRUGS — the group Basil interacts with.

Theoretically, basil might increase the risk of hypotension when taken with antihypertensive drugs.
Animal research suggests that basil extract can reduce systolic and diastolic blood pressure.
Severity Moderate Likelihood Possible Evidence D

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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the simple version: Ziac already lowers your blood pressure two ways. The bisoprolol is a beta-blocker that slows your heart and eases pressure, and the hydrochlorothiazide is a water pill that helps your body shed extra fluid and salt. Basil, in lab and animal studies, has shown a mild blood-pressure-lowering effect of its own. So in theory, piling concentrated basil on top of your medicine could nudge your pressure a little too low.

I want to be honest, though, this is weak, theoretical evidence from animal research, not from people. Basil sprinkled on your pasta or pesto is not going to cause trouble. Concentrated basil supplements or essential oils are the real question mark. If you go that route, watch for dizziness, lightheadedness, or feeling faint when you stand, and check with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Umar, A., Imam, G., Yimin, W., Kerim, P., Tohti, I., Berke, B., and Moore, N. Antihypertensive effects of Ocimum basilicum L. (OBL) on blood pressure in renovascular hypertensive rats. Hypertens.Res 5-7-2010; PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction 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.
  • PossibleInteraction 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.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Basil Also Interacts With Other Medications

Basil has 288 moderate known drug interactions in our database — the Bisoprolol, Hydrochlorothiazide one above is one of them. If you take anything else, check it against the full list below.

Moderate 288 No known interaction 2,542 (incl. Bisoprolol, Hydrochlorothiazide)
Taking anything else?

Check Another of Your Medications Against Basil

Covers the 2,830 medications we’ve checked against Basil. Pick one to open its full report.

From our Q&A

Questions About Basil or Bisoprolol, Hydrochlorothiazide

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Basil or Bisoprolol, Hydrochlorothiazide, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Bisoprolol, Hydrochlorothiazide

This page covers Basil only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Bisoprolol, Hydrochlorothiazide page lists 276 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Asarabacca (major) and Dolomite (major).

By severity: 11 major · 234 moderate · 31 minor.

From our pharmacist’s overview on the Bisoprolol, Hydrochlorothiazide page

“This is one of the supplement lists I would read closely before adding anything alongside bisoprolol and hydrochlorothiazide (Ziac). The combination already lowers blood pressure two ways, and most of these interactions push on those same levers, either dropping pressure further or acting like extra diuretics that compound potassium an…”

Reviewed by 2 · Jul 18, 2026

Open the Bisoprolol, Hydrochlorothiazide interaction page

One more smart check

Taking Basil as Part of a Dietary Supplement Product? Check It for Interactions

We hold 396 real supplement products containing Basil, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Basil. Your product may carry other ingredients that interact with Bisoprolol, Hydrochlorothiazide too, on top of Basil — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Basil and Bisoprolol, Hydrochlorothiazide Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Basil
Top 25%

#362 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Bisoprolol, Hydrochlorothiazide
Top 25%

#680 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Basil

What is Basil?

Basil
  • Digestive upset and gas
  • Stress and anxiety
  • Antimicrobial support
  • Cold and cough symptoms
  • Headache
  • General antioxidant support

Basil is a popular cooking herb that is generally safe in the amounts used in food. While it has a long history of traditional medicinal use and contains antioxidant compounds, strong human evidence for most health claims is limited. Talk with your pharmacist or doctor before using concentrated supplements or essential oils.

Read the full Basil monograph & all interactions
Keep checking

Other Drugs & Basil

Browse every other medication we’ve checked against Basil — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
288Moderate
0Minor
2,541No known interaction
288 Moderate 2,541 No interaction
Moderate

288 interactions

Showing 60 of 288 moderate interactions — see all 288 on the Basil page.

No interaction 2,541 drugs checked — show the list

We also checked Basil against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,541 medications checked with no known interaction — see the full Basil list.

See the full Basil interactions page
See every supplement checked against Bisoprolol, Hydrochlorothiazide, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Basil monograph › Uses, safety, and every drug interaction in one place Bisoprolol, Hydrochlorothiazide supplement interactions › Every supplement checked against Bisoprolol, Hydrochlorothiazide, ranked by severity Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Basil and Bisoprolol, Hydrochlorothiazide Together: Common Questions

Can you take Basil with Bisoprolol, Hydrochlorothiazide?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Basil and Bisoprolol, Hydrochlorothiazide interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Bisoprolol, Hydrochlorothiazide and Basil?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.