Drug & supplement interaction

California Poppy + Codeine Phosphate

Codeine Phosphate brand name: Codeine.

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

California Poppy has a moderate interaction with Codeine Phosphate. Theoretically, taking California poppy with drugs with sedative effects may increase the risk of sedative effects.

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

California Poppy and Codeine Phosphate

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

Moderate

CNS DEPRESSANTS

Why this applies to Codeine Phosphate

Codeine Phosphate falls under CNS DEPRESSANTS — the group California Poppy interacts with.

Theoretically, taking California poppy with drugs with sedative effects may increase the risk of sedative effects.
Laboratory research shows that California poppy has sedative effects.
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: codeine is an opioid that calms the brain and nervous system, and California poppy seems to do something similar. When you stack two things that both have a calming effect, those effects can add up. With codeine, that might show up as feeling extra drowsy or foggy, more dizziness, slower thinking, or in larger amounts, slower breathing. So the concern here is mainly about too much sedation, not a change in how well codeine treats your pain or cough.

I want to be honest about the evidence though. This warning comes from lab and animal research, not solid human studies, so it's more of a theoretical caution than a proven problem. Still, since codeine already makes some people sleepy, it's worth a quick chat with your pharmacist or doctor before combining the two.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Paul LD, Springer D, Staack RF, et al. Cytochrome P450 isoenzymes involved in rat liver microsomal metabolism of californine and protopine. Eur J Pharmacol 2004;485:69-79. PubMed
  2. Paul LD, Maurer HH. Studies on the metabolism and toxicological detection of the Eschscholtzia californica alkaloids californine and protopine in urine using gas chromatography-mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2003;789:43-5

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

California Poppy Also Interacts With Other Medications

California Poppy has 247 moderate known drug interactions in our database — the Codeine Phosphate 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. Codeine Phosphate)
Taking anything else?

Check Another of Your Medications Against California Poppy

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

From our Q&A

Questions About California Poppy or Codeine Phosphate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers California Poppy or Codeine Phosphate, 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 Codeine Phosphate

This page covers California Poppy only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Codeine Phosphate page lists 144 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: 7 major · 114 moderate · 23 minor.

From our pharmacist’s overview on the Codeine Phosphate page

“Codeine phosphate is an opioid painkiller and cough suppressant that slows breathing along with brain activity, and the wrong supplement can push that effect into dangerous territory. Seven of the 144 documented ingredients rate major, and nearly all of that serious risk comes from things that deepen sedation.”

Reviewed by 2 · Jul 18, 2026

Open the Codeine Phosphate interaction page

One more smart check

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

We hold 345 real supplement products containing California Poppy, each one broken down to its full ingredient list — and combination products often carry several ingredients besides California Poppy. Your product may carry other ingredients that interact with Codeine Phosphate too, on top of California Poppy — 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 California Poppy and Codeine Phosphate 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 California Poppy
Top half

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

29 days ago today
Medication Codeine Phosphate
Top 25%

#386 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 California Poppy

What is California Poppy?

California Poppy
  • Anxiety and stress
  • Trouble sleeping (insomnia)
  • Mild aches and pains
  • Restlessness or nervous tension
  • Bedwetting in children (traditional use)

California poppy is a traditional herbal remedy used mainly for anxiety and sleep problems, often combined with other calming herbs. Human research is very limited, so its true benefits are not well proven. It is generally considered mild, but should be avoided during pregnancy and breastfeeding and used with caution by anyone taking sedating medicines.

Read the full California Poppy monograph & all interactions
Medication

About Codeine

What Is Codeine Used For?

Brand name: Codeine

Codeine Sulfate tablets are used for the management of mild to moderate pain in adults and adolescents when other treatments have not worked well enough or are not tolerated. It is an opioid medication, so it is only appropriate when non-opioid options are inadequate.

Because of its serious risks — including addiction, misuse, and overdose — codeine is reserved for patients who truly need an opioid. Prescribers are expected to use the lowest effective dose for the shortest time possible.

See full Codeine drug information
Keep checking

Other Drugs & California Poppy

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

No interaction 2,582 drugs checked — show the list

We also checked California Poppy 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 California Poppy list.

See the full California Poppy interactions page
See every supplement checked against Codeine Phosphate, 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
California Poppy monograph › Uses, safety, and every drug interaction in one place Codeine Phosphate supplement interactions › Every supplement checked against Codeine Phosphate, ranked by severity Codeine 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 California Poppy and Codeine Phosphate Together: Common Questions

Can you take California Poppy with Codeine Phosphate?
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 California Poppy and Codeine Phosphate 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 Codeine Phosphate and California Poppy?

Our pharmacists answer your medication & supplement questions — free.

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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.