Drug & supplement interaction

Bay Leaf + 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 2 drug categories that Bay Leaf can interact with; the most serious is rated moderate. Theoretically, taking bay leaf in large amounts may enhance the therapeutic and adverse effects of sedatives.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Bay Leaf and Aspirin, Caffeine, Dihydrocodeine Bitartrate

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Bay Leaf interacts with whole categories of medication. Aspirin, Caffeine, Dihydrocodeine Bitartrate falls into 2 of those categories, so it can interact with Bay Leaf 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, Caffeine, Dihydrocodeine Bitartrate

Aspirin, Caffeine, Dihydrocodeine Bitartrate falls under CNS DEPRESSANTS — the group Bay Leaf interacts with.

Theoretically, taking bay leaf in large amounts may enhance the therapeutic and adverse effects of sedatives.
Bay leaf contains methyl eugenol. Animal research shows that methyl eugenol has sedative properties. Avoid concomitant use.
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: this combo product (Synalgos DC) includes dihydrocodeine, an opioid pain reliever that can already make you sleepy. Bay leaf contains a compound called methyl eugenol, which in animal studies showed mild sedative effects. So the theory is that taking concentrated bay leaf could add to that drowsiness and deepen the calming effect of the opioid.

To be clear, this is a theoretical concern only, and the bay leaf you sprinkle in soup or stew won't matter. The worry is with strong supplements or essential oils. If those were stacked on top of this medication, you might notice extra sleepiness, dizziness, or feeling foggy. Caffeine in the product may offset some of that, but not reliably. Please check with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
Moderate

NARCOTIC DRUGS

2 of 2

Aspirin, Caffeine, Dihydrocodeine Bitartrate also falls under NARCOTIC DRUGS.

Theoretically, taking bay leaf in large amounts may enhance the therapeutic and adverse effects of narcotics. Avoid concomitant use.
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

Synalgos DC contains dihydrocodeine, a narcotic pain reliever, along with aspirin and caffeine. The idea here is mostly a theoretical one: in larger, concentrated amounts, bay leaf compounds might add to the calming effects of narcotics. If that happened, you could feel more of the things dihydrocodeine already does, like extra drowsiness, dizziness, slowed breathing, or more constipation. There is no strong human proof of this, and the small amount of bay leaf used to season a pot of soup is very unlikely to cause any problem.

The caution really applies to bay leaf supplements or essential oils, not your cooking. If you take Synalgos DC and also use concentrated bay leaf products, check with your pharmacist or doctor first. Please don't change anything on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.

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

Bay Leaf Also Interacts With Other Medications

Bay Leaf has 334 moderate 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 334 No known interaction 2,496 (incl. Aspirin, Caffeine, Dihydrocodeine Bitartrate)
Taking anything else?

Check Another of Your Medications Against Bay Leaf

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

Everything else you take

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

This page covers Bay Leaf 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

How much people look this up

Where Bay Leaf 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 Bay Leaf
Top 25%

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

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

#1,532 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 Bay Leaf

What is Bay Leaf?

Bay Leaf
  • Cooking and flavoring
  • Digestive upset
  • Blood sugar support
  • Colds and congestion
  • Joint and muscle discomfort

Bay leaf is a common culinary herb that is safe in the small amounts used in cooking. Some people take it for digestion, blood sugar, or colds, but strong human evidence for these uses is lacking. Talk to your pharmacist or doctor before using concentrated supplements or essential oils.

Read the full Bay Leaf monograph & all interactions
Keep checking

Other Drugs & Bay Leaf

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

0Major
334Moderate
0Minor
2,495No known interaction
334 Moderate 2,495 No interaction
Moderate

334 interactions

Showing 60 of 334 moderate interactions — see all 334 on the Bay Leaf page.

No interaction 2,495 drugs checked — show the list

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

Showing the 60 most looked-up of 2,495 medications checked with no known interaction — see the full Bay Leaf list.

See the full Bay Leaf 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
Bay Leaf 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 Bay Leaf and Aspirin, Caffeine, Dihydrocodeine Bitartrate Together: Common Questions

Can you take Bay Leaf 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 2 interactions listed for Bay Leaf and Aspirin, Caffeine, Dihydrocodeine Bitartrate?
Aspirin, Caffeine, Dihydrocodeine Bitartrate belongs to more than one drug category, and Bay Leaf 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 Bay Leaf 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.