Herb & supplement monograph

Flaxseed Oil Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Flaxseed Oil interacts with medications. The heart of this page is the interaction list — every drug Flaxseed Oil is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Flaxseed Oil is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Interaction report

Drugs that interact with Flaxseed Oil

293 medications have a known interaction with Flaxseed Oil, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Flaxseed Oil using our pharmacist-reviewed interaction data.

AI summaries are generated from our Flaxseed Oil interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction 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.
Possible. 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
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Flaxseed Oil combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Flaxseed Oil affects

Every type of medication (drug category) Flaxseed Oil is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 3 drug categories Flaxseed Oil interacts with

Anticoagulant/antiplatelet DrugsAntihypertensive DrugsEzetimibe (zetia)

Anticoagulant/Antiplatelet Drugs

Theoretically, using flaxseed oil in combination with anticoagulant or antiplatelet drugs might have additive effects and increase the risk of bleeding.
Small clinical studies show that consuming flaxseed oil might decrease platelet aggregation and increase bleeding time.

Likelihood Possible Evidence D

Antihypertensive Drugs

Theoretically, combining flaxseed oil with other antihypertensive drugs might have additive effects and increase the risk of hypotension.
Some clinical evidence suggests that long-term consumption of flaxseed oil can modestly lower systolic and diastolic blood pressure, while other clinical research shows no effect.

Likelihood Possible Evidence D

Ezetimibe (Zetia)

Concomitant use of flaxseed oil and ezetimibe reduces the absorption of alpha-linolenic acid from flaxseed oil.
In one clinical study, concomitant consumption of ezetimibe 10 mg daily with flaxseed oil 2 grams providing 1 gram of alpha-linolenic acid daily blocked the absorption of alpha-linolenic acid, resulting in an overall reduction in alpha-linolenic plasma levels from baseline.

Likelihood Probable Evidence B

Monograph

Flaxseed Oil: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Flaxseed oil is a plant-based source of the omega-3 fatty acid ALA, which the body can partly convert to the omega-3s found in fish oil. It may help support heart health and provide healthy fats, but evidence for most specific health claims is limited or mixed. It is generally well tolerated, but talk to your pharmacist or doctor before starting, especially if you are pregnant or have a bleeding risk.

Scientific name: Linum usitatissimum
Family: Linaceae
Part used: Oil pressed from the seeds
Common forms: Liquid oil, softgel capsules, salad oil

People commonly use it for

Source of omega-3 (ALA) fatty acids
Heart and cholesterol health
Dry skin and inflammation
Constipation
General wellness

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Generally well tolerated for most adults, but quality and dose vary by product.

PregnancyPossibly Safe

When used orally and appropriately for medicinal purposes, short-term. Although flaxseed oil has been used with apparent safety in clinical research i...

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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Overview

Flaxseed oil comes from the seeds of the flax plant (Linum usitatissimum), a plant grown around the world for its fiber and seeds. The oil is pressed from the ripe seeds and is rich in a plant omega-3 fatty acid called alpha-linolenic acid, or ALA.

People use flaxseed oil as a dietary source of healthy fats. It is sold as a liquid oil that can be added to food and as softgel capsules. It is different from whole or ground flaxseed, which also contains fiber and plant compounds called lignans that the oil mostly lacks.

How it works

The main active ingredient in flaxseed oil is alpha-linolenic acid (ALA), an omega-3 fatty acid. The body can convert a small amount of ALA into the longer-chain omega-3s (EPA and DHA) that are also found in fish oil, though this conversion is limited and varies from person to person.

Omega-3 fats are thought to play a role in reducing inflammation and supporting the heart and blood vessels. Much of this understanding comes from laboratory studies, animal research, and studies of omega-3s in general rather than flaxseed oil specifically.

Effectiveness

Does Flaxseed Oil work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 27 uses evaluated

4 Leans ineffective 23 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

Possibly Ineffective Bipolar disorder