Drug & supplement interaction

Rosemary + Aspirin, Caffeine, Dihydrocodeine Bitartrate

Aspirin, Caffeine, Dihydrocodeine Bitartrate brand name: Synalgos DC.

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

Aspirin, Caffeine, Dihydrocodeine Bitartrate falls into 3 drug categories that Rosemary can interact with; the most serious is rated moderate. Theoretically, rosemary may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Rosemary and Aspirin, Caffeine, Dihydrocodeine Bitartrate

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Rosemary interacts with whole categories of medication. Aspirin, Caffeine, Dihydrocodeine Bitartrate falls into 3 of those categories, so it can interact with Rosemary in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

1 of 3

Why this applies to Aspirin, Caffeine, Dihydrocodeine Bitartrate

Aspirin, Caffeine, Dihydrocodeine Bitartrate falls under ANTICOAGULANT/ANTIPLATELET DRUGS — the group Rosemary interacts with.

Theoretically, rosemary may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
In vitro and animal research suggests that rosemary inhibits platelet aggregation.
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 thing to know about this combo: the aspirin in Synalgos DC already thins your blood a bit by keeping platelets from clumping together. Rosemary may do something similar. In lab dishes and animal studies, rosemary compounds slowed platelet activity too, so stacking the two could, in theory, nudge your bleeding risk a little higher. Think easier bruising, nosebleeds, or bleeding that takes longer to stop.

I want to be honest though, this is theoretical and based only on early lab and animal work, not on people. A little rosemary in your cooking is no worry at all. Concentrated rosemary capsules or oil are where I'd pause. If you take those regularly, just run it by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Lee JJ, Jin YR, Lee JH, et al. Antiplatelet activity of carnosic acid, a phenolic diterpene from Rosmarinus officinalis. Planta Med 2007;73(2):121-7.
  2. Yamamoto J, Yamada K, Naemura A, et al. Testing various herbs for antithrombotic effect. Nutrition 2005;21(5):580-7. PubMed
  3. Naemura A, Ura M, Yamashita T, et al. Long-term intake of rosemary and common thyme herbs inhibits experimental thrombosis without prolongation of bleeding time. Thromb Res 2008;122(4):517-22. PubMed
  4. Lee JJ, Jin YR, Lim Y, et al. Antiplatelet activity of carnosol is mediated by the inhibition of TXA2 receptor and cytosolic calcium mobilization. Vascul Pharmacol 2006;45:148-53. PubMed
Moderate

ASPIRIN

2 of 3
Theoretically, rosemary might have additive effects with salicylate-containing drugs such as aspirin.
Rosemary is reported to contain salicylates.
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. Synalgos DC contains aspirin, which is a salicylate. Rosemary is reported to naturally contain small amounts of salicylates too. So in theory, piling rosemary on top of your aspirin could nudge your total salicylate load a little higher, which might add to aspirin's usual effects like stomach upset, heartburn, or a slightly greater chance of bruising or bleeding.

I want to keep this in perspective. This concern comes only from lab and animal-type evidence, not from real patient cases, and the rosemary you sprinkle on chicken or potatoes is very unlikely to matter at all. Concentrated rosemary supplements are where I'd be a bit more cautious. Before adding a rosemary supplement, just run it past your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Swain AR, Dutton SP, Truswell AS. Salicylates in foods. J Am Diet.Assoc 1985;85(8):950-60. DOI
Minor

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

3 of 3

Aspirin, Caffeine, Dihydrocodeine Bitartrate also falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES.

Theoretically, rosemary might decrease the levels and clinical effects of CYP1A2 substrates.
In vitro research shows that rosemary induces CYP1A2 enzymes. This effect has not been reported in humans.
Severity Minor Likelihood Unlikely Evidence D

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the piece that matters most in your Synalgos DC combo: the caffeine. Caffeine is cleared by a liver enzyme called CYP1A2, and lab studies hint that rosemary might speed that enzyme up a little. If that happened in real life, your body could clear caffeine faster, so you might feel a bit less of its perk and notice the mild alertness wearing off sooner.

The honest truth is this is only seen in test tube and animal studies, never confirmed in people, so it's rated minor and unlikely. Everyday rosemary in cooking is no concern at all. The dihydrocodeine and aspirin parts aren't really affected by this pathway. Still, if you use concentrated rosemary supplements regularly, mention it to your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Debersac P, Heydel JM, Amiot MJ, et al. Induction of cytochrome P450 and/or detoxication enzymes by various extracts of rosemary: description of specific patterns. Food Chem Toxicol 2001;39(9):907-18. PubMed
  2. Debersac P, Vernevaut MF, Amiot MJ, et al. Effects of a water-soluble extract of rosemary and its purified component rosmarinic acid on xenobiotic-metabolizing enzymes in rat liver. Food Chem Toxicol 2001;39(2):109-17. 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

Rosemary Also Interacts With Other Medications

Rosemary has 211 moderate, 160 minor known drug interactions in our database — the Aspirin, Caffeine, Dihydrocodeine Bitartrate one above is among them. If you take anything else, check it against the full list below.

Moderate 211 Minor 160 No known interaction 2,459 (incl. Aspirin, Caffeine, Dihydrocodeine Bitartrate)
Taking anything else?

Check Another of Your Medications Against Rosemary

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

Everything else you take

See Every Supplement That Interacts With Aspirin, Caffeine, Dihydrocodeine Bitartrate

This page covers Rosemary only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Aspirin, Caffeine, Dihydrocodeine Bitartrate page lists 398 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 · 334 moderate · 47 minor.

Open the Aspirin, Caffeine, Dihydrocodeine Bitartrate interaction page

One more smart check

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

We hold 1,786 real supplement products containing Rosemary, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Rosemary. Your product may carry other ingredients that interact with Aspirin, Caffeine, Dihydrocodeine Bitartrate too, on top of Rosemary — 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 Rosemary and Aspirin, Caffeine, Dihydrocodeine Bitartrate 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 Rosemary
Top 25%

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

29 days ago today
Medication Aspirin, Caffeine, Dihydrocodeine Bitartrate
Steady interest

#1,472 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 Rosemary

What is Rosemary?

Rosemary
  • Memory and concentration
  • Digestive upset
  • Hair growth
  • Anxiety and stress (aromatherapy)
  • Muscle and joint discomfort
  • Antioxidant support

Rosemary is a fragrant Mediterranean herb that is safe and flavorful in normal food amounts. Some early research suggests possible benefits for memory, mood, and hair growth, but the evidence is limited and far from conclusive. Concentrated supplements and the essential oil should be used carefully, and the essential oil should never be swallowed.

Read the full Rosemary monograph & all interactions
Keep checking

Other Drugs & Rosemary

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

0Major
211Moderate
160Minor
2,458No known interaction
211 Moderate 160 Minor 2,458 No interaction
Moderate

211 interactions

Showing 60 of 211 moderate interactions — see all 211 on the Rosemary page.

Minor

160 interactions

Showing 60 of 160 minor interactions — see all 160 on the Rosemary page.

No interaction 2,458 drugs checked — show the list

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

Showing the 60 most looked-up of 2,458 medications checked with no known interaction — see the full Rosemary list.

See the full Rosemary interactions page
See every supplement checked against Aspirin, Caffeine, Dihydrocodeine Bitartrate, 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
Rosemary monograph › Uses, safety, and every drug interaction in one place Aspirin, Caffeine, Dihydrocodeine Bitartrate supplement interactions › Every supplement checked against Aspirin, Caffeine, Dihydrocodeine Bitartrate, 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 Rosemary and Aspirin, Caffeine, Dihydrocodeine Bitartrate Together: Common Questions

Can you take Rosemary with Aspirin, Caffeine, Dihydrocodeine Bitartrate?
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 3 interactions listed for Rosemary and Aspirin, Caffeine, Dihydrocodeine Bitartrate?
Aspirin, Caffeine, Dihydrocodeine Bitartrate belongs to more than one drug category, and Rosemary 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 Rosemary and Aspirin, Caffeine, Dihydrocodeine Bitartrate 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

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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.