Drug & supplement interaction

Catnip + Morphine Sulfate

Morphine Sulfate brand names: MS Contin, Kadian, Avinza, Morphabond, Arymo ER.

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

Catnip has a moderate interaction with Morphine Sulfate. Theoretically, concomitant use with drugs with sedative properties may cause additive effects and side effects.

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

Catnip and Morphine Sulfate

Here is the interaction we found between these two, with the evidence behind it.

Moderate

CNS DEPRESSANTS

Why this applies to Morphine Sulfate

Morphine Sulfate falls under CNS DEPRESSANTS — the group Catnip interacts with.

Theoretically, concomitant use with drugs with sedative properties may cause additive effects and side effects.
Clinical and animal research shows that catnip has sedative properties.
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

Here's the simple version: morphine already slows down your brain and nervous system, which is how it eases pain but also why it can make you drowsy, foggy, or slow your breathing. Catnip, usually taken as a calming tea, seems to have mild sedative effects of its own. Put the two together and those effects could stack up, leaving you more sleepy, dizzy, or sluggish than you'd expect.

To be honest, this is a theoretical concern based mostly on animal studies and anecdotes, not strong human research. A cup of catnip tea probably isn't a big deal for most people, but concentrated supplements could matter more. Since morphine is a powerful opioid, please run this by your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  2. Osterhoudt KC, Lee SK, Callahan JM, Henretig FM. Catnip and the alteration of human consciousness. Vet Hum Toxicol 1997;39:373-5.
  3. Sherry, C. J. and Hunter, P. S. The effect of an ethanol extract of catnip (Nepeta cataria) on the behavior of the young chick. Experientia 2-15-1979;35(2):237-238. PubMed
  4. Harney, J. W., Barofsky, I. M., and Leary, J. D. Behavioral and toxicological studies of cyclopentanoid monoterpenes from Nepeta cataria. Lloydia. 1978;41(4):367-374.
  5. Massoco, C. O., Silva, M. R., Gorniak, S. L., Spinosa, M. S., and Bernardi, M. M. Behavioral effects of acute and long-term administration of catnip (Nepeta cataria) in mice. Vet.Hum.Toxicol 1995;37(6):530-533.

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

Catnip Also Interacts With Other Medications

Catnip has 247 moderate known drug interactions in our database — the Morphine Sulfate one above is one of them. If you take anything else, check it against the full list below.

Moderate 247 No known interaction 2,583 (incl. Morphine Sulfate)
Taking anything else?

Check Another of Your Medications Against Catnip

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

From our Q&A

Questions About Catnip or Morphine Sulfate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Catnip or Morphine Sulfate, 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 Morphine Sulfate

This page covers Catnip only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Morphine Sulfate page lists 172 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), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Kava (major).

By severity: 8 major · 138 moderate · 26 minor.

From our pharmacist’s overview on the Morphine Sulfate page

“With morphine sulfate (MS Contin, Kadian, Avinza), an opioid powerful enough to slow breathing on its own, this list warrants genuine respect. Of the 172 supplements and foods on file, 8 carry a major rating, and most of those pile extra sedation onto a drug that already sedates.”

Reviewed by 2 · Jul 18, 2026

Open the Morphine Sulfate interaction page

One more smart check

Taking Catnip as Part of a Dietary Supplement Product? Check It for Interactions

We hold 295 real supplement products containing Catnip, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Catnip. Your product may carry other ingredients that interact with Morphine Sulfate too, on top of Catnip — 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 Catnip and Morphine Sulfate 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 Catnip
Top half

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

29 days ago today
Medication Morphine Sulfate
Steady interest

#1,613 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 Catnip

What is Catnip?

Catnip
  • Sleep and insomnia
  • Anxiety and stress
  • Digestive upset
  • Cold and flu symptoms
  • Insect repellent

Catnip is a mint-family herb most often used as a calming tea for sleep, anxiety, and minor digestive upset, but solid human research supporting these uses is lacking. It is generally considered fairly safe in small culinary or tea amounts for most adults, but it should be avoided during pregnancy and used cautiously otherwise. Talk to your pharmacist or doctor before using it, especially if you take medications or have a health condition.

Read the full Catnip monograph & all interactions
Medication

About Morphine

What Is Morphine Used For?

Brand names: MS Contin, Kadian, Avinza, Morphabond, Arymo ER

Morphine is used to manage acute (short-term) and chronic (long-term) pain that is severe enough to need an opioid and that hasn't been adequately treated by other options. The higher-concentration liquid form is reserved for adults who are already opioid-tolerant — meaning their body is used to opioid medications.

Because of real risks of addiction, misuse, and overdose, morphine is only prescribed when other pain treatments have not worked or are not expected to work. It is not intended for long-term use unless the pain continues to be severe and no alternatives are suitable.

See full Morphine drug information
Keep checking

Other Drugs & Catnip

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

0Major
247Moderate
0Minor
2,582No known interaction
247 Moderate 2,582 No interaction
Moderate

247 interactions

Showing 60 of 247 moderate interactions — see all 247 on the Catnip page.

No interaction 2,582 drugs checked — show the list

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

Showing the 60 most looked-up of 2,582 medications checked with no known interaction — see the full Catnip list.

See the full Catnip interactions page
See every supplement checked against Morphine Sulfate, 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
Catnip monograph › Uses, safety, and every drug interaction in one place Morphine Sulfate supplement interactions › Every supplement checked against Morphine Sulfate, ranked by severity Morphine drug information › The full plain-English guide to this medication 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 Catnip and Morphine Sulfate Together: Common Questions

Can you take Catnip with Morphine Sulfate?
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.
How serious is the Catnip and Morphine Sulfate 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 Morphine Sulfate and Catnip?

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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.