Drug & supplement interaction

Lemongrass + Diltiazem

Diltiazem brand names: Cardizem, Cardizem SR, Diltiaz SR, Cardizem CD, Tiazac, and others.

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

Lemongrass has a moderate interaction with Diltiazem. Theoretically, lemongrass might decrease the metabolism of CYP3A4 substrates.

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

Lemongrass and Diltiazem

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

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Diltiazem

Diltiazem falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Lemongrass interacts with.

Theoretically, lemongrass might decrease the metabolism of CYP3A4 substrates.
Animal research shows that lemongrass and its constituent citral inhibit CYP3A4.
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 basic idea: your liver uses an enzyme called CYP3A4 to break down diltiazem and clear it out. Lemongrass, mainly through a compound called citral, may slow that enzyme down. If the enzyme works slower, diltiazem can hang around longer and build up in your body, which could make its effects stronger than expected.

With diltiazem, that might show up as a blood pressure that drops too low, dizziness, a slower heartbeat, tiredness, or swelling in the ankles. I want to be honest, though: this concern comes only from lab and animal studies, not human research, so it's largely theoretical. The lemongrass in cooking or an occasional tea is unlikely to matter. Concentrated capsules or the essential oil are where I'd be more careful, so check with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Li CC, Yu HF, Chang CH, Liu YT, Yao HT. Effects of lemongrass oil and citral on hepatic drug-metabolizing enzymes, oxidative stress, and acetaminophen toxicity in rats. J Food Drug Anal 2018;26(1):432-8. 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

Lemongrass Also Interacts With Other Medications

Lemongrass has 707 moderate known drug interactions in our database — the Diltiazem one above is one of them. If you take anything else, check it against the full list below.

Moderate 707 No known interaction 2,123 (incl. Diltiazem)
Taking anything else?

Check Another of Your Medications Against Lemongrass

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

From our Q&A

Questions About Lemongrass or Diltiazem

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Lemongrass or Diltiazem, 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 Diltiazem

This page covers Lemongrass only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Diltiazem page lists 260 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), Coleus (major) and Grapefruit (major).

By severity: 7 major · 214 moderate · 39 minor.

From our pharmacist’s overview on the Diltiazem page

“Someone on diltiazem (Cardizem, Tiazac) is usually managing blood pressure, angina, or a fast heart rhythm, so this list deserves genuine care. Seven of the 260 ingredients on file carry a major rating, and two of those are things people actually buy: grapefruit, which blocks the enzyme that clears diltiazem and can push its blood leve…”

Reviewed by 2 · Jul 18, 2026

Open the Diltiazem interaction page

One more smart check

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

We hold 417 real supplement products containing Lemongrass, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Lemongrass. Your product may carry other ingredients that interact with Diltiazem too, on top of Lemongrass — 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 Lemongrass and Diltiazem 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 Lemongrass
Top half

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

29 days ago today
Medication Diltiazem
Top 10%

#278 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 Lemongrass

What is Lemongrass?

Lemongrass
  • Digestive upset
  • Anxiety and stress
  • Antimicrobial/antifungal
  • Insect repellent
  • Flavoring in food and drinks

Lemongrass is a fragrant tropical grass widely used as a cooking herb, a tea, and an aromatherapy oil. It is generally considered safe in the small amounts used in food, but most of its claimed health benefits come from laboratory or animal studies rather than strong human research. Talk with your pharmacist or doctor before using concentrated supplements or the essential oil, especially if you are pregnant or breastfeeding.

Read the full Lemongrass monograph & all interactions
Medication

About Diltiazem

What Is Diltiazem Used For?

Brand names: Cardizem, Cardizem SR, Diltiaz SR, Cardizem CD, Tiazac, Diltiaz XT, Diltiaz CD, Dilacor, Diltiaz, Cardizem LA, Dilacor XR, Cartia XT, Tiamate, Adizem-SR, Adizem-XL, Angitil SR, Angitil XL, Calcicard CR, Dilcardia SR, Dilzem SR, Dilzem XL, Slozem, Tildiem LA, Tildiem Retard, Viazem XL, Zemtard 120XL, Zemtard 180XL, Zemtard 240XL, Zemtard 300XL

Oral extended-release forms of diltiazem — including Matzim LA, Cardizem LA, Cartia, Cartia XT, Tiadylt ER, and various generic capsules and tablets — are used to treat high blood pressure (hypertension) and chronic stable angina (chest pain brought on by activity). Some capsule formulations, including Cartia, Cartia XT, and certain generics, are also approved for angina due to coronary artery spasm (sudden chest pain caused by a sudden tightening of a coronary artery).

Injectable forms of diltiazem are used in hospital settings to temporarily slow a dangerously fast heart rate in atrial fibrillation or atrial flutter (rapid, irregular heart rhythms), and to restore a normal heart rhythm in paroxysmal supraventricular tachycardia (PSVT) — sudden episodes of a very fast but regular heartbeat originating above the heart's lower chambers.

See full Diltiazem drug information
Keep checking

Other Drugs & Lemongrass

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

0Major
707Moderate
0Minor
2,122No known interaction
707 Moderate 2,122 No interaction
Moderate

707 interactions

Showing 60 of 707 moderate interactions — see all 707 on the Lemongrass page.

No interaction 2,122 drugs checked — show the list

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

Showing the 60 most looked-up of 2,122 medications checked with no known interaction — see the full Lemongrass list.

See the full Lemongrass interactions page
See every supplement checked against Diltiazem, 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
Lemongrass monograph › Uses, safety, and every drug interaction in one place Diltiazem supplement interactions › Every supplement checked against Diltiazem, ranked by severity Diltiazem drug information › The full plain-English guide to this medication 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 Lemongrass and Diltiazem Together: Common Questions

Can you take Lemongrass with Diltiazem?
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 Lemongrass and Diltiazem 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 Diltiazem and Lemongrass?

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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.