Herb & supplement monograph

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

But these pages have grown well beyond that into a full monograph — what Celery 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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Celery Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Celery drug interaction appears low for most people. None of the listed interactions are rated major, and most rest on lab, animal, or theoretical findings rather than confirmed problems in people.

Interactions deserving the most attention

The best-documented concern involves blood pressure medications: human research found celery seed extract lowered systolic blood pressure by a meaningful amount, so adding it could drop pressure more than expected. Levothyroxine also deserves attention, since several people stable on this thyroid medicine developed low thyroid levels after starting celery seed tablets and recovered once they stopped. Because celery may act as a mild diuretic, it could in theory raise lithium levels, though this has not been confirmed in people.

What the rest of the list means

The long list of hundreds of interacting medications looks alarming, but most entries are theoretical. Many stem from lab findings that celery might slow an enzyme the body uses to clear certain medicines, an effect never actually reported in humans. Concerns such as increased bleeding with blood thinners likewise come from laboratory research only.

Check your medications against Celery

Based on HelloPharmacist’s Celery interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Celery

651 medications have a known interaction with Celery, 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 Celery using our pharmacist-reviewed interaction data.

AI summaries are generated from our Celery 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 Celery 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 Celery affects

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

All 8 drug categories Celery interacts with

Anticoagulant/antiplatelet DrugsAntihypertensive DrugsCytochrome P450 1a2 (cyp1a2) SubstratesLevothyroxine (synthroid, Others)LithiumVenlafaxine (effexor)Acetaminophen (tylenol, Others)Photosensitizing Drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, celery root might increase the risk of bleeding when taken with anticoagulant/antiplatelet drugs.
Celery root contains the constituents falcarinol and falcarindiol. Laboratory research suggests that these constituents can inhibit platelet aggregation. This effect has not been reported in humans.

Likelihood Possible Evidence D

Antihypertensive Drugs

Theoretically, celery seed extract might have additive effects with antihypertensive drugs.
Clinical research suggests that taking celery seed extract may reduce daytime systolic blood pressure by about 12 mmHg compared to less than 1 mmHg with placebo.

Likelihood Probable Evidence B

Cytochrome P450 1A2 (Cyp1A2) Substrates

Theoretically, celery might increase levels of drugs metabolized by CYP1A2.
In vitro and animal research suggests that constituents of celery can inhibit CYP1A2. This effect has not been reported in humans.

Likelihood Possible Evidence D

Levothyroxine (Synthroid, Others)

Theoretically, celery seed might decrease the effects of levothyroxine.
Several cases of hypothyroidism with low T4 levels have been reported in people who were previously stabilized on levothyroxine and then started taking celery seed tablets. They presented with symptoms such as lethargy, bloating, and dry skin, and recovered when celery seed was stopped. However, celery stem and leaf has been associated with case reports of hyperthyroidism in patients with no pre-existing thyroid disorders.

Likelihood Possible Evidence D

Lithium

Theoretically, celery might reduce excretion and increase levels of lithium due to potential diuretic effects.
Celery is thought to have diuretic properties. However, this effect has not been confirmed in humans.

Likelihood Probable Evidence D

Venlafaxine (Effexor)

Theoretically, celery root extract might increase blood levels of venlafaxine.
There is one case report of a patient who experienced medication-induced bipolar disorder after beginning to take celery root extract 1000 mg daily along with venlafaxine 75 mg and St. John's wort 600 mg daily. Symptoms included confusion, speech abnormalities, manic affect, and visual hallucinations. The plasma level of venlafaxine was 476.8 ng/mL (normal range 195-400 ng/mL). It is theorized that celery root increased venlafaxine levels by inhibiting cytochrome P450 2D6.

Likelihood Possible Evidence D

Acetaminophen (Tylenol, Others)

Theoretically, celery juice might increase the effects and side effects of acetaminophen.
Animal research suggests that concomitant use of celery juice plus acetaminophen prolongs the effects of acetaminophen. This effect has been attributed to a decrease in hepatic cytochrome P450 activity. However, other animal research shows that pretreatment with celery root extract protects against acetaminophen-induced acute liver failure. These effects have not been reported in humans.

Likelihood Possible Evidence D

Photosensitizing Drugs

Theoretically, celery might increase the risk of photosensitivity reactions when taken with photosensitizing drugs.
Laboratory research shows that celery contains photosensitizing agents such as phenols and psoralens.

Likelihood Possible Evidence D

Monograph

Celery: Uses, Safety & Side Effects

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

The bottom line

Celery is a common vegetable that is also taken as a seed extract or oil supplement, mainly for blood pressure, fluid retention, and joint discomfort. Human evidence for these supplement uses is limited and mostly preliminary, so it should not replace proven treatments. Celery is generally safe as food, but concentrated supplements and possible allergic reactions warrant caution.

Scientific name: Apium graveolens
Family: Apiaceae
Part used: Stalks, seeds, and seed oil (sometimes the whole plant and root)
Common forms: Fresh vegetable, juice, seed powder, capsules, tablets, and seed oil extract

People commonly use it for

High blood pressure
Fluid retention (diuretic)
Joint pain and inflammation
Anxiety and sleep
Digestive support

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

Safety at a glance

OverallUse caution

Generally safe as food, but concentrated supplements and allergy risk call for some caution.

PregnancyLikely Unsafe

When celery oil or seeds are used orally in larger amounts; celery might have uterine stimulant or abortifacient effects.

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

There is insufficient reliable information available about the safety of medicinal amounts of celery during lactation; 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

Celery (Apium graveolens) is a plant in the carrot and parsley family. Its crunchy stalks are a popular vegetable, and it is grown around the world. The seeds, root, and oil from the seeds are also used.

As a food, celery is low in calories and provides vitamins and minerals such as vitamin K, potassium, and folate, along with antioxidant plant compounds.

When celery is used as a dietary supplement, it is usually a celery seed extract or celery seed oil rather than the stalk. People take it hoping to support healthy blood pressure, reduce fluid retention, and ease joint discomfort.

How it works

Celery contains several plant compounds that researchers have studied, including phthalides (such as 3-n-butylphthalide), flavonoids like apigenin and luteolin, and antioxidants.

In laboratory and animal studies, phthalides may help relax blood vessel walls, which could lower blood pressure. Flavonoids and other compounds may act as antioxidants and reduce inflammation.

Celery may also have a mild diuretic effect, meaning it can increase urine output. It is important to remember that most of this information comes from test-tube and animal research, and the effects in people are not well proven.

Effectiveness

Does Celery work?

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

Evidence overview · 14 uses evaluated

14 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.

For Celery, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 14 conditions — evidence insufficient to rate

Insufficient Reliable Evidence To Rate Anxiety