Drug & supplement interaction

Tarragon + Codeine Phosphate, Guaifenesin

Codeine Phosphate, Guaifenesin brand names: Brontex, Robitussin AC.

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

Tarragon has a moderate interaction with Codeine Phosphate, Guaifenesin. Evidence from animal research suggests that tarragon essential oil can cause sedation and motor impairment when administered intraperitoneally at a dose of 1 mL/kg.

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

Tarragon and Codeine Phosphate, Guaifenesin

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

Moderate

CNS DEPRESSANTS

Why this applies to Codeine Phosphate, Guaifenesin

Codeine Phosphate, Guaifenesin falls under CNS DEPRESSANTS — the group Tarragon interacts with.

Evidence from animal research suggests that tarragon essential oil can cause sedation and motor impairment when administered intraperitoneally at a dose of 1 mL/kg. Theoretically, concomitant use of tarragon with CNS depressants, including antihistamines, barbiturates, benzodiazepines, and tricyclic antidepressants, may increase sedative and other adverse 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: your cough syrup pairs codeine, an opioid that can make you drowsy, with guaifenesin, which loosens mucus. The concern with tarragon is purely about sleepiness stacking up. In animal studies, concentrated tarragon essential oil caused sedation and shaky coordination. The worry is that piling tarragon on top of a sedating medicine like codeine could deepen that effect.

So in theory you might feel extra groggy, lightheaded, or slow to react, which matters if you're driving. But be reassured: this is only lab and animal data, not proven in people, and a pinch of tarragon in cooking is very unlikely to do anything. Concentrated extracts or the essential oil are where I'd be cautious. Check with your pharmacist before adding tarragon supplements.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sayyah, M., Nadjafnia, L., and Kamalinejad, M. Anticonvulsant activity and chemical composition of Artemisia dracunculus L. essential oil. J Ethnopharmacol. 2004;94(2-3):283-287. 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

Tarragon Also Interacts With Other Medications

Tarragon has 358 moderate known drug interactions in our database — the Codeine Phosphate, Guaifenesin one above is one of them. If you take anything else, check it against the full list below.

Moderate 358 No known interaction 2,472 (incl. Codeine Phosphate, Guaifenesin)
Taking anything else?

Check Another of Your Medications Against Tarragon

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

Everything else you take

See Every Supplement That Interacts With Codeine Phosphate, Guaifenesin

This page covers Tarragon only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Codeine Phosphate, Guaifenesin 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.

Open the Codeine Phosphate, Guaifenesin interaction page

One more smart check

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

We hold 36 real supplement products containing Tarragon, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Tarragon. Your product may carry other ingredients that interact with Codeine Phosphate, Guaifenesin too, on top of Tarragon — 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 Tarragon and Codeine Phosphate, Guaifenesin 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 Tarragon
Top half

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

29 days ago today
Medication Codeine Phosphate, Guaifenesin
Top 10%

#200 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 Tarragon

What is Tarragon?

Tarragon
  • Digestive upset
  • Appetite stimulation
  • Sleep and mild restlessness
  • Toothache and oral discomfort
  • Blood sugar support (preliminary)
  • Culinary flavoring

Tarragon is a flavorful culinary herb that has been used in traditional medicine for digestion, sleep, and other complaints, but solid human evidence for any health benefit is lacking. Amounts used in cooking are generally considered safe, while concentrated extracts and the essential oil should be used cautiously because tarragon contains estragole, a compound studied for possible safety concerns. Talk to your pharmacist or doctor before using tarragon as a supplement.

Read the full Tarragon monograph & all interactions
Keep checking

Other Drugs & Tarragon

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

0Major
358Moderate
0Minor
2,471No known interaction
358 Moderate 2,471 No interaction
Moderate

358 interactions

Showing 60 of 358 moderate interactions — see all 358 on the Tarragon page.

No interaction 2,471 drugs checked — show the list

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

Showing the 60 most looked-up of 2,471 medications checked with no known interaction — see the full Tarragon list.

See the full Tarragon interactions page
See every supplement checked against Codeine Phosphate, Guaifenesin, 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
Tarragon monograph › Uses, safety, and every drug interaction in one place Codeine Phosphate, Guaifenesin supplement interactions › Every supplement checked against Codeine Phosphate, Guaifenesin, 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 Tarragon and Codeine Phosphate, Guaifenesin Together: Common Questions

Can you take Tarragon with Codeine Phosphate, Guaifenesin?
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 Tarragon and Codeine Phosphate, Guaifenesin 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, Guaifenesin and Tarragon?

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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.