Drug & supplement interaction

Cnidium + 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 Cnidium can interact with; the most serious is rated moderate. In laboratory research, cnidium has been shown to have sedative and hypnotic effects, possibly related to constituent coumarins.

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

Cnidium and Aspirin, Codeine Phosphate, Methocarbamol

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

Why Are There 2 Interactions?

Cnidium interacts with whole categories of medication. Aspirin, Codeine Phosphate, Methocarbamol falls into 2 of those categories, so it can interact with Cnidium 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 Cnidium interacts with.

In laboratory research, cnidium has been shown to have sedative and hypnotic effects, possibly related to constituent coumarins. Theoretically, cnidium may potentiate the effects of barbiturates, other sedatives, and anxiolytics.
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 combo pill Robaxisal C carries two ingredients that already make you drowsy: codeine (an opioid) and methocarbamol (a muscle relaxant). In lab and animal studies, cnidium has shown its own sedative, sleep-promoting effect, likely from its coumarin compounds. So the worry here is simple addition: piling a calming supplement on top of two calming medicines could leave you more groggy than expected.

Keep in mind this is theoretical, based only on test-tube and animal work, not human studies. Still, if you stacked them, you might notice extra sleepiness, dizziness, slowed thinking, or in a worst case, slower breathing from the codeine. Please check with your pharmacist or doctor before mixing them, and don't change your medicine on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sun Y, Yang AWH, Lenon GB. Phytochemistry, ethnopharmacology, pharmacokinetics and toxicology of Cnidium monnieri (L.) Cusson. Int J Mol Sci. 2020;21(3):1006. PubMed
Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

2 of 2

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

Laboratory research shows that osthol, a constituent of cnidium, inhibits blood clotting and the activity of platelets. Theoretically, cnidium might increase the risk of bleeding when used with antiplatelet or anticoagulant drugs.
Some anticoagulant or antiplatelet drugs include aspirin, clopidogrel (Plavix), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, ticlopidine (Ticlid), warfarin (Coumadin), and others.
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 this combo pill that matters here is the aspirin. Aspirin already thins your blood by keeping platelets (your tiny clotting cells) from sticking together. Lab studies suggest a compound in cnidium called osthole does something similar, slowing clotting on its own. Stack the two and, in theory, you could bleed a little more easily, think easy bruising, nosebleeds, or a cut that takes longer to stop.

I want to be honest about the strength of this: it comes from test tube and animal research, not real patients, so it's more of a caution than a proven problem. The codeine and methocarbamol parts aren't the concern. Before adding a cnidium supplement, run it by your pharmacist or doctor, especially if you bruise easily or take other blood thinners.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sun Y, Yang AWH, Lenon GB. Phytochemistry, ethnopharmacology, pharmacokinetics and toxicology of Cnidium monnieri (L.) Cusson. Int J Mol Sci. 2020;21(3):1006. 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

Cnidium Also Interacts With Other Medications

Cnidium 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 Cnidium

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

Everything else you take

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

This page covers Cnidium 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 Cnidium as Part of a Dietary Supplement Product? Check It for Interactions

We hold 175 real supplement products containing Cnidium, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cnidium. Your product may carry other ingredients that interact with Aspirin, Codeine Phosphate, Methocarbamol too, on top of Cnidium — 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 Cnidium 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 Cnidium
Top half

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

29 days ago today
Medication Aspirin, Codeine Phosphate, Methocarbamol
Top 25%

#526 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 Cnidium

What is Cnidium?

Cnidium
  • Skin conditions and itching
  • Erectile dysfunction and low libido
  • Eczema and dermatitis
  • Antifungal or antimicrobial washes
  • Athletic performance
  • General antioxidant support

Cnidium is the dried fruit of an Asian plant long used in traditional Chinese medicine, mostly for skin problems and sexual health. Modern human evidence for these uses is very limited, with most research coming from laboratory and animal studies. Talk with your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Read the full Cnidium monograph & all interactions
Keep checking

Other Drugs & Cnidium

Browse every other medication we’ve checked against Cnidium — 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 Cnidium page.

No interaction 2,479 drugs checked — show the list

We also checked Cnidium 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 Cnidium list.

See the full Cnidium 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
Cnidium 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 Cnidium and Aspirin, Codeine Phosphate, Methocarbamol Together: Common Questions

Can you take Cnidium 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 Cnidium and Aspirin, Codeine Phosphate, Methocarbamol?
Aspirin, Codeine Phosphate, Methocarbamol belongs to more than one drug category, and Cnidium 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 Cnidium 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 Cnidium?

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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.