Drug & supplement interaction

Maritime Pine + Fluorouracil (IV)

Fluorouracil (IV) brand name: Fluorouracil.

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

Maritime Pine has a moderate interaction with Fluorouracil (IV). Theoretically, maritime pine bark extract might decrease the effectiveness of immunosuppressant therapy.

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

Maritime Pine and Fluorouracil (IV)

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

Moderate

IMMUNOSUPPRESSANTS

Why this applies to Fluorouracil (IV)

Fluorouracil (IV) falls under IMMUNOSUPPRESSANTS — the group Maritime Pine interacts with.

Theoretically, maritime pine bark extract might decrease the effectiveness of immunosuppressant therapy.
In vitro and animal research suggests that maritime pine bark extract has immunostimulant activity. This effect has not been reported in humans.
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 honest picture with Pycnogenol (maritime pine bark) and IV fluorouracil (5-FU). The concern on file is theoretical: in lab dishes and animal studies, pine bark seemed to give the immune system a little nudge (immunostimulant activity). Since fluorouracil works partly by suppressing fast-dividing cells, the worry is that this kind of supplement could work against that effect. To be clear, this has never actually been shown in people, so the evidence here is weak.

That said, fluorouracil is serious chemotherapy with real side effects like mouth sores, diarrhea, and low blood counts, and your oncology team plans it carefully. I wouldn't add maritime pine on your own during treatment. Please run it by your oncologist or pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Rice-Evans CA, Packer L, eds. Flavonoids in Health and Disease. Manhattan, NY: Marcel Dekker, Inc., 1998.
  2. Liu FJ, Zhang YX, Lau BH. Pycnogenol enhances immune and haemopoietic functions in senescence-accelerated mice. Cell Mol Life Sci 1998;54:1168-72. 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

Maritime Pine Also Interacts With Other Medications

Maritime Pine has 326 moderate known drug interactions in our database — the Fluorouracil (IV) one above is one of them. If you take anything else, check it against the full list below.

Moderate 326 No known interaction 2,504 (incl. Fluorouracil (IV))
Taking anything else?

Check Another of Your Medications Against Maritime Pine

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

Everything else you take

See Every Supplement That Interacts With Fluorouracil (IV)

This page covers Maritime Pine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fluorouracil (IV) page lists 59 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Active Hexose Correlated Compound (ahcc) (moderate), Alfalfa (moderate), American Ginseng (moderate), Andrographis (moderate) and Ashwagandha (moderate).

By severity: 58 moderate · 1 minor.

From our pharmacist’s overview on the Fluorouracil (IV) page

“Fluorouracil is an IV chemotherapy medicine, and the supplement list attached to it is manageable for most people once you see the single thread running through it. Nearly all 59 entries are herbs and extracts believed to stimulate the immune system, ashwagandha, astragalus, and medicinal mushroom products among them, and the concern i…”

Reviewed by 2 · Jul 18, 2026

Open the Fluorouracil (IV) interaction page

One more smart check

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

We hold 452 real supplement products containing Maritime Pine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Maritime Pine. Your product may carry other ingredients that interact with Fluorouracil (IV) too, on top of Maritime Pine — 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 Maritime Pine and Fluorouracil (IV) 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 Maritime Pine
Top 25%

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

29 days ago today
Medication Fluorouracil (IV)
Steady interest

#1,808 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 Maritime Pine

What is Maritime Pine?

Maritime Pine
  • Circulation and vein health
  • Antioxidant support
  • Skin health and aging
  • High blood pressure
  • Joint comfort

Maritime pine bark extract (often sold as Pycnogenol) is a plant-based antioxidant most studied for circulation, vein, and skin health. Some research is promising, but many studies are small or industry-funded, so benefits are not firmly proven. It is generally well tolerated, but talk to your pharmacist or doctor before starting it.

Read the full Maritime Pine monograph & all interactions
Keep checking

Other Drugs & Maritime Pine

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

0Major
326Moderate
0Minor
2,503No known interaction
326 Moderate 2,503 No interaction
Moderate

326 interactions

Showing 60 of 326 moderate interactions — see all 326 on the Maritime Pine page.

No interaction 2,503 drugs checked — show the list

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

Showing the 60 most looked-up of 2,503 medications checked with no known interaction — see the full Maritime Pine list.

See the full Maritime Pine interactions page
See every supplement checked against Fluorouracil (IV), 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
Maritime Pine monograph › Uses, safety, and every drug interaction in one place Fluorouracil (IV) supplement interactions › Every supplement checked against Fluorouracil (IV), 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 Maritime Pine and Fluorouracil (IV) Together: Common Questions

Can you take Maritime Pine with Fluorouracil (IV)?
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 Maritime Pine and Fluorouracil (IV) 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.