Drug & supplement interaction

Cnidium + Aspirin, Diphenhydramine, Phenylpropanolamine

Aspirin, Diphenhydramine, Phenylpropanolamine brand name: Alka Seltzer Plus Night Time Effervescent.

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

Aspirin, Diphenhydramine, Phenylpropanolamine 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, Diphenhydramine, Phenylpropanolamine

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, Diphenhydramine, Phenylpropanolamine 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, Diphenhydramine, Phenylpropanolamine

Aspirin, Diphenhydramine, Phenylpropanolamine 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 product you're asking about already contains diphenhydramine (the same ingredient as Benadryl), which on its own makes most people drowsy. In lab and animal studies, cnidium has shown calming, sleep-inducing effects of its own, likely tied to its natural coumarin compounds. So the worry here is simple addition: pairing the two could leave you more sedated than expected, with extra grogginess, dizziness, a foggy head, or trouble staying alert to drive.

Keep in mind this is a theoretical concern based only on laboratory work, not human studies, so it may not amount to much. Still, since this medicine is meant for nighttime use and already causes sleepiness, it's worth a quick chat with your pharmacist or doctor before combining them.

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, Diphenhydramine, Phenylpropanolamine 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 combo product you're asking about contains aspirin, which on its own thins the blood by keeping platelets from sticking together. Cnidium, mainly through a compound called osthole, appears to do something similar in lab studies, slowing clotting and platelet activity. Put them together and, in theory, you could lean a little harder on the bleeding side: think easier bruising, nosebleeds, bleeding gums, or a cut that takes longer to stop.

I want to be honest about the evidence here. This is based on test tube and animal research, not real-world human studies, so it's more of a caution than a proven problem. The diphenhydramine and phenylpropanolamine pieces aren't really involved. Still, if you take this regularly or have any bleeding concerns, check with your pharmacist or doctor before adding cnidium.

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, Diphenhydramine, Phenylpropanolamine 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, Diphenhydramine, Phenylpropanolamine)
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, Diphenhydramine, Phenylpropanolamine

This page covers Cnidium only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Aspirin, Diphenhydramine, Phenylpropanolamine page lists 361 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: 17 major · 308 moderate · 36 minor.

From our pharmacist’s overview on the Aspirin, Diphenhydramine, Phenylpropanolamine page

“A cold remedy used for a few nights can still collide with supplements taken daily, and Alka Seltzer Plus Night Time (aspirin, diphenhydramine, phenylpropanolamine) is one to treat with genuine care. Its three ingredients thin the blood, sedate, and stimulate all at once, which is why 361 supplements and herbs are on file here.”

Reviewed by 2 · Jul 18, 2026

Open the Aspirin, Diphenhydramine, Phenylpropanolamine 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, Diphenhydramine, Phenylpropanolamine 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, Diphenhydramine, Phenylpropanolamine 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

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

29 days ago today
Medication Aspirin, Diphenhydramine, Phenylpropanolamine
Top 10%

#248 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, Diphenhydramine, Phenylpropanolamine, 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, Diphenhydramine, Phenylpropanolamine supplement interactions › Every supplement checked against Aspirin, Diphenhydramine, Phenylpropanolamine, 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, Diphenhydramine, Phenylpropanolamine Together: Common Questions

Can you take Cnidium with Aspirin, Diphenhydramine, Phenylpropanolamine?
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, Diphenhydramine, Phenylpropanolamine?
Aspirin, Diphenhydramine, Phenylpropanolamine 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, Diphenhydramine, Phenylpropanolamine 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, Diphenhydramine, Phenylpropanolamine 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.