Drug & supplement interaction

Magnolia + Aspirin, Codeine Phosphate, Methocarbamol

Aspirin, Codeine Phosphate, Methocarbamol brand name: Robaxisal C.

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

Aspirin, Codeine Phosphate, Methocarbamol 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, Methocarbamol

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, Methocarbamol 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, Methocarbamol

Aspirin, Codeine Phosphate, Methocarbamol 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 (Robaxisal C) already has two ingredients that can make you drowsy: codeine, an opioid pain reliever, and methocarbamol, a muscle relaxer. Magnolia bark may add to that calming, sleepy effect. Lab and animal studies suggest magnolol and honokiol act on GABA pathways in the brain, the same kind of pathways that produce sedation. So stacking magnolia on top could leave you feeling extra groggy, dizzy, or foggy, with slower breathing in higher doses.

Keep in mind this is theoretical, based on cell and animal research, and most likely matters only with concentrated magnolia supplements rather than small amounts. Still, please check with your pharmacist or doctor before pairing them, especially before driving.

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, Methocarbamol 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

The piece of your combination tablet that matters here is the aspirin. Aspirin already thins the blood by keeping platelets from clumping together. Magnolia bark contains two compounds, magnolol and honokiol, that in lab dish studies also slowed platelet clumping. Stacked together, the worry is a little extra bleeding tendency, things like easier bruising, nosebleeds, or a cut that takes longer to stop.

I want to be honest about how soft this evidence is. It's theoretical, seen only in test tubes, and has never actually been reported in real people. So it's worth being aware of, not alarmed about. If you take this regularly or have any bleeding issues, just run it by your pharmacist or doctor before adding a magnolia supplement.

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, Methocarbamol 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, Methocarbamol)
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, Methocarbamol

This page covers Magnolia only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Aspirin, Codeine Phosphate, Methocarbamol page lists 328 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 · 282 moderate · 34 minor.

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

“Alcohol is the single riskiest thing to combine with Robaxisal C (aspirin, codeine phosphate, and methocarbamol). Beer and wine both carry major ratings backed by solid human evidence, because codeine and methocarbamol already slow breathing and reflexes, and alcohol deepens that sedation.”

Reviewed by 2 · Jul 18, 2026

Open the Aspirin, Codeine Phosphate, Methocarbamol 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, Methocarbamol 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, Methocarbamol 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, Methocarbamol
Top 25%

#550 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, Methocarbamol, 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, Methocarbamol supplement interactions › Every supplement checked against Aspirin, Codeine Phosphate, Methocarbamol, 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, Methocarbamol Together: Common Questions

Can you take Magnolia with Aspirin, Codeine Phosphate, Methocarbamol?
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, Methocarbamol?
Aspirin, Codeine Phosphate, Methocarbamol 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, Methocarbamol 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 Aspirin, Codeine Phosphate, Methocarbamol 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.