Drug & supplement interaction

Magnolia + Aspirin, Codeine Phosphate, Phenobarbital

Aspirin, Codeine Phosphate, Phenobarbital brand name: Phenaphen.

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

Aspirin, Codeine Phosphate, Phenobarbital falls into 2 drug categories that Magnolia can interact with; the most serious is rated moderate. Theoretically, concomitant use of large doses of magnolia bark and CNS depressants might have additive effects.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Magnolia and Aspirin, Codeine Phosphate, Phenobarbital

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Magnolia interacts with whole categories of medication. Aspirin, Codeine Phosphate, Phenobarbital falls into 2 of those categories, so it can interact with Magnolia in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CNS DEPRESSANTS

1 of 2

Why this applies to Aspirin, Codeine Phosphate, Phenobarbital

Aspirin, Codeine Phosphate, Phenobarbital falls under CNS DEPRESSANTS — the group Magnolia interacts with.

Theoretically, concomitant use of large doses of magnolia bark and CNS depressants might have additive effects.
In vitro and animal research shows that constituents extracted from magnolia bark, especially honokiol and magnolol, have sedative effects. These effects may be due to the inhibition of catecholamine release and modulation of gamma-aminobutyric acid-A (GABA-A) receptors.
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

This combination product packs two ingredients that already calm the brain: codeine (an opioid) and phenobarbital (a barbiturate). Magnolia bark, thanks to its honokiol and magnolol, seems to nudge the same GABA pathways, so layering it on top could add to that sedating effect. In plain terms, you might feel extra drowsy, foggy, dizzy, or slowed down in your breathing, especially with the phenobarbital piece.

Now, the honest part: this warning comes from lab dishes and animal studies, not from people, so it's more of a theoretical caution than a proven problem. Food or tea amounts of magnolia likely don't matter much, but concentrated supplement doses could. Please run it past your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  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
Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

2 of 2

Aspirin, Codeine Phosphate, Phenobarbital also falls under ANTICOAGULANT/ANTIPLATELET DRUGS.

Theoretically, magnolia might have additive effects and increase the risk of bleeding when used with anticoagulant or antiplatelet drugs.
In vitro research shows that the chemicals magnolol and honokiol, isolated from magnolia bark, inhibit platelet aggregation that is experimentally induced by collagen and arachidonic acid. However, they do not inhibit platelet aggregation that is induced by adenosine diphosphate, platelet-activating factor, or thrombin. This interaction has not been reported in humans.
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

This combo product (Phenaphen) already contains aspirin, which thins the blood by blocking platelets so they don't clump as easily. Magnolia bark may do a little of the same thing. In lab dish studies, the compounds magnolol and honokiol slowed platelet clumping triggered by certain pathways. Stacked on top of aspirin, the worry is added bleeding risk, things like easier bruising, nosebleeds, bleeding gums, or stomach upset.

Important context: this is purely theoretical, based on test-tube work, and has not actually been seen in people. So I wouldn't panic. Still, if you take this medicine regularly and want to try magnolia, run it by your pharmacist or doctor first, especially before any surgery or dental work.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Teng CM, Chen CC, Ko FN, et al. Two antiplatelet agents from Magnolia officinalis. Thromb Res 1988;50:757-65. 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

Magnolia Also Interacts With Other Medications

Magnolia has 350 moderate known drug interactions in our database — the Aspirin, Codeine Phosphate, Phenobarbital one above is among them. If you take anything else, check it against the full list below.

Moderate 350 No known interaction 2,480 (incl. Aspirin, Codeine Phosphate, Phenobarbital)
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.

Everything else you take

See Every Supplement That Interacts With Aspirin, Codeine Phosphate, Phenobarbital

This page covers Magnolia only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Aspirin, Codeine Phosphate, Phenobarbital page lists 352 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Asarabacca (major), Beer (major) and Danshen (major).

By severity: 12 major · 304 moderate · 36 minor.

From our pharmacist’s overview on the Aspirin, Codeine Phosphate, Phenobarbital page

“Alcohol is the entry I would flag first with Phenaphen (aspirin, codeine phosphate, phenobarbital): beer or wine layered onto codeine and phenobarbital can deepen sedation and, at worst, slow breathing. This medication deserves real caution with supplements.”

Reviewed by 2 · Jul 18, 2026

Open the Aspirin, Codeine Phosphate, Phenobarbital 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. Your product may carry other ingredients that interact with Aspirin, Codeine Phosphate, Phenobarbital too, on top of Magnolia — 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 Magnolia and Aspirin, Codeine Phosphate, Phenobarbital 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%

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

29 days ago today
Medication Aspirin, Codeine Phosphate, Phenobarbital
Top 10%

#255 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 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.

Read the full Magnolia monograph & all interactions
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
350Moderate
0Minor
2,479No known interaction
350 Moderate 2,479 No interaction
Moderate

350 interactions

Showing 60 of 350 moderate interactions — see all 350 on the Magnolia page.

No interaction 2,479 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 2,479 medications checked with no known interaction — see the full Magnolia list.

See the full Magnolia interactions page
See every supplement checked against Aspirin, Codeine Phosphate, Phenobarbital, 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
Magnolia monograph › Uses, safety, and every drug interaction in one place Aspirin, Codeine Phosphate, Phenobarbital supplement interactions › Every supplement checked against Aspirin, Codeine Phosphate, Phenobarbital, 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 Magnolia and Aspirin, Codeine Phosphate, Phenobarbital Together: Common Questions

Can you take Magnolia with Aspirin, Codeine Phosphate, Phenobarbital?
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.
Why are there 2 interactions listed for Magnolia and Aspirin, Codeine Phosphate, Phenobarbital?
Aspirin, Codeine Phosphate, Phenobarbital belongs to more than one drug category, and Magnolia interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Magnolia and Aspirin, Codeine Phosphate, Phenobarbital 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

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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.