Drug & supplement interaction

Magnolia + Diltiazem

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

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Magnolia and Diltiazem in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Magnolia and Diltiazem

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Diltiazem and Magnolia in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Magnolia safety at a glance

Magnolia overall Use caution May be okay short-term for many adults, but human safety data is limited.
Pregnancy Unsafe When the magnolia flower bud is used orally due to reports of uterine stimulant activity. There is insufficient reliable information available about the safety... Read the full pregnancy detail
Breastfeeding Avoid No reliable safety data during breastfeeding, so it is best avoided.

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Diltiazem and Magnolia? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Diltiazem

Interactions in our licensed database are recorded against drug classes, not just single drug names. Diltiazem is filed under 9 classifications — including calcium channel blockers, cytochrome p450 1a2 (cyp1a2) inhibitors, cytochrome p450 3a4 (cyp3a4) inhibitors. Magnolia has documented interactions with 2 drug classes — the most serious being anticoagulant/antiplatelet drugs (moderate) and cns depressants (moderate) — and none of Diltiazem’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Magnolia Does Interact With Other Medications

Magnolia has 351 moderate known drug interactions in our database — Diltiazem isn’t one of them. If you take anything else, check it against the full list below.

Moderate 351 No known interaction 2,479 (incl. Diltiazem)
Taking anything else?

Check Another of Your Medications Against Magnolia

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

What to actually watch for

No Interaction Found — But Data Suggests Magnolia and Diltiazem May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Erection problems Additional detail

    Magnolia

    “In a clinical trial of an oral combination product containing extracts of magnolia and phellodendron, one patient reported sexual dysfunction. However, it's not known if this side effect is related to magnolia or some other factor.”

    Magnolia · Natural Medicines adverse-effect record, reported in antidepressant-induced sexual dysfunction.

    1 source cited
    1. 14349. Garrison R, Chambliss WG. Effect of a proprietary Magnolia and Phellodendron extract on weight management: a pilot, double-blind, placebo-controlled clinical trial. Altern Ther Health Med 2006;12:50-4.

    Diltiazem

    Listed in the ADVERSE REACTIONS section of the FDA label for Diltiazem. Read the label on DailyMed ›

  • Numbness or tingling / Tiredness / Headache reported in 7.9% of FDA reports for Diltiazem Additional detail

    Magnolia

    “In a clinical trial of an oral combination product containing extracts of magnolia and phellodendron, one patient reported shaking hands and perilabial numbness. Another patient reported fatigue and headache. However, it's not known if these side effects are related to magnolia or some other factor.”

    Magnolia · Natural Medicines adverse-effect record, reported in cluster headache.

    1 source cited
    1. 14349. Garrison R, Chambliss WG. Effect of a proprietary Magnolia and Phellodendron extract on weight management: a pilot, double-blind, placebo-controlled clinical trial. Altern Ther Health Med 2006;12:50-4.

    Diltiazem

    Listed in the ADVERSE REACTIONS section of the FDA label for Diltiazem, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • A skin rash Additional detail

    Magnolia

    “Topically, magnolia bark has been associated with reports of allergic contact dermatitis. In several cases, the use of anti-aging facial creams containing magnolia bark extract was associated with allergic contact dermatitis of the face. In one case, the use of a vaginal gel containing magnolia bark extract was associated with allergic contact dermatitis of the vulva.”

    Magnolia · Natural Medicines adverse-effect record, reported in dermatitis.

    4 sources cited
    1. 92463. Ghys K, De Palma A, Vandevenne A, Werbrouck J, Goossens A. Magnolia officinalis bark extract, a recently identified contact allergen in 'anti-ageing' cosmetics. Contact Dermatitis. 2015 Aug;73(2):130-2.
    2. 92468. Raison-Peyron N, Césaire A, Du-Thanh A, Dereure O. Allergic contact dermatitis caused by Magnolia officinalis bark extract in a facial anti-ageing cream. Contact Dermatitis. 2015 Jun;72(6):416-7.
    3. 95030. Nilausen TD, Johansen JD, Thyssen JP. Allergic contact dermatitis of the face caused by Magnolia officinalis bark extract. Contact Dermatitis. 2016;75(6):385-87.
    4. 110709. Amat-Samaranch V, López-Sánchez C, Tubau C, Puig L, Serra-Baldrich E. Vulvar allergic contact dermatitis caused by Magnolia officinalis bark extract. Contact Dermatitis 2022;87(1):96-97.

    Diltiazem

    Listed in the ADVERSE REACTIONS section of the FDA label for Diltiazem. Read the label on DailyMed ›

Reported for Magnolia but not commonly for Diltiazem: heartburn and tremor or shakiness.

Effects for Diltiazem come from the ADVERSE REACTIONS section of its FDA label; effects for Magnolia come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 34,400 voluntary FDA FAERS reports for Diltiazem that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Magnolia in Pregnancy & Breastfeeding

Pregnancy Unsafe

When the magnolia flower bud is used orally due to reports of uterine stimulant activity. There is insufficient reliable information available about the safety of using magnolia bark during pregnancy; avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

Questions About Magnolia 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 Magnolia 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 Magnolia 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 Magnolia as Part of a Dietary Supplement Product? Check It for Interactions

We hold 736 real supplement products containing Magnolia, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Magnolia. Even though Magnolia itself has no known interaction with Diltiazem, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Magnolia 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 Magnolia
Top 25%

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

29 days ago today
Medication Diltiazem
Top 5%

#134 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Magnolia reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Magnolia and Diltiazem records this page draws on were last updated July 11, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Magnolia

What is Magnolia?

Magnolia
  • Anxiety and stress
  • Sleep problems
  • Digestive upset
  • Inflammation
  • Nasal congestion and allergies (flower bud)

Magnolia bark and flower buds have a long history in traditional Chinese and Japanese medicine, often for stress, sleep, and digestion. Modern human research is still limited, so we can't be sure how well it works for most uses. Talk with your pharmacist or doctor before trying it, especially if you take other medicines or are pregnant.

Magnolia officinalis · Magnoliaceae · Bark and flower buds · Capsules, tablets, tea, tinctures, and some toothpastes or skin products

An interaction check asks whether these two react with each other — it does not ask whether Magnolia is a good idea for someone in your situation. Here is what our Magnolia record says about it on its own.

Magnolia: dosing

There is no well-established standard dose of Magnolia. Products vary widely in how they are prepared and how concentrated they are, and many supplements combine Magnolia with other ingredients.The safest approach is to follow the directions on the product label and not exceed the recommended amount.

From our Magnolia monograph — the full record covers uses, side effects and every documented interaction.

Read the full Magnolia 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.

Most-Reported Side Effects for Diltiazem

From FAERS, the FDA’s public side-effect reporting system (34,400 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Dyspnea 3,309 reports
Fatigue 2,733 reports
Nausea 2,454 reports
Dizziness 2,174 reports
Diarrhea 2,113 reports
See full Diltiazem drug information
Keep checking

Other Drugs & Magnolia

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

0Major
351Moderate
0Minor
2,478No known interaction
351 Moderate 2,478 No interaction
Moderate

351 interactions

Showing 60 of 351 moderate interactions — see all 351 on the Magnolia page.

No interaction 2,478 drugs checked — show the list

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

Showing the 60 most looked-up of 2,478 medications checked with no known interaction — see the full Magnolia list.

See the full Magnolia interactions page
See every supplement checked against Diltiazem, ranked by severity
Evidence & sources

Magnolia References

The 9 references that drive our Magnolia monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Kuribara H, Kishi E, Hattori N, et al. The anxiolytic effect of two oriental herbal drugs in Japan attributed to honokiol from magnolia bark. J Pharm Pharmacol 2000;52:1425-9. PubMed
  2. Tachikawa E, Takahashi M, Kashimoto T. Effects of extract and ingredients isolated from Magnolia obovata thunberg on catecholamine secretion from bovine adrenal chromaffin cells. Biochem Pharmacol 2000;60:433-40. PubMed
  3. Jung KY, Kim DS, Oh SR, et al. Magnone A and B, novel anti-PAF tetrahydrofuran lignans from the flower buds of Magnolia fargesii. J Nat Prod 1998;61:808-11.
  4. Garrison R, Chambliss WG. Effect of a proprietary Magnolia and Phellodendron extract on weight management: a pilot, double-blind, placebo-controlled clinical trial. Altern Ther Health Med 2006;12:50-4.
  5. Teng CM, Chen CC, Ko FN, et al. Two antiplatelet agents from Magnolia officinalis. Thromb Res 1988;50:757-65. PubMed
  6. Ghys K, De Palma A, Vandevenne A, Werbrouck J, Goossens A. Magnolia officinalis bark extract, a recently identified contact allergen in 'anti-ageing' cosmetics. Contact Dermatitis. 2015 Aug;73(2):130-2.
  7. Raison-Peyron N, Césaire A, Du-Thanh A, Dereure O. Allergic contact dermatitis caused by Magnolia officinalis bark extract in a facial anti-ageing cream. Contact Dermatitis. 2015 Jun;72(6):416-7.
  8. Nilausen TD, Johansen JD, Thyssen JP. Allergic contact dermatitis of the face caused by Magnolia officinalis bark extract. Contact Dermatitis. 2016;75(6):385-87.
  9. Amat-Samaranch V, López-Sánchez C, Tubau C, Puig L, Serra-Baldrich E. Vulvar allergic contact dermatitis caused by Magnolia officinalis bark extract. Contact Dermatitis 2022;87(1):96-97.

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Magnolia and Diltiazem Together: Common Questions

Is it safe to take Magnolia with Diltiazem?
We do not list a known interaction between Magnolia and Diltiazem. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Magnolia and Diltiazem have any of the same side effects?
Yes — our sources link each of them separately to 5 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
How was the Magnolia and Diltiazem combination checked?
Interactions in our licensed database are recorded against drug classes. Diltiazem is filed under 9 classifications, and Magnolia has documented interactions with 2 drug classes — none of Diltiazem's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Magnolia interact with any other medications?
Yes. Magnolia has 351 documented drug interactions in our database — Diltiazem is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Diltiazem interact with any supplements?
Yes. Diltiazem has documented interactions with 260 supplements in our database — Magnolia is not one of them. The Diltiazem interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Magnolia monograph Uses, safety profile, and every drug interaction in one place Diltiazem drug information The full plain-English guide to this medication Diltiazem supplement interactions Every supplement checked against Diltiazem, 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 References The 9 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Diltiazem and Magnolia?

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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.