Interaction Checker

Check interactions

Add your supplements, foods, meals — and any medications you take — to see how they interact. Findings are grouped by severity: what to avoid, what needs care or timing, and what actually works better together.

St. John's Wort

Add more (1/12)

Add a medication you take (optional)

Avoid

64 · Don't combine without medical guidance

Avoid

St. John's WortMany prescription drugs

St. John's Wort lowers blood levels of many drugs (and can cause serotonin syndrome with antidepressants).

Why: Potent inducer of CYP3A4 and P-glycoprotein; serotonergic activity.

→ Do not combine with prescription medications without your prescriber's sign-off.

Curated

Avoid

St. John's WortCyclosporine

Reduces cyclosporine levels 40-60%, causing organ rejection

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortTacrolimus

Reduces tacrolimus levels, causing organ rejection

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortSirolimus

Reduces sirolimus levels, transplant rejection risk

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortWarfarin

Reduces INR, increases clotting/stroke risk

Why: CYP2C9 induction

Known interaction

Avoid

St. John's WortDigoxin

Reduces digoxin levels 25-40%, cardiac arrhythmia risk

Why: P-glycoprotein induction

Known interaction

Avoid

St. John's WortIndinavir

Reduces indinavir levels 57%, HIV treatment failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortRitonavir

Significantly reduces levels, treatment failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortSaquinavir

Reduces levels 49%, treatment failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortNevirapine

Reduces levels, HIV treatment failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortEfavirenz

Reduces levels, treatment failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortAtazanavir

Contraindicated - significant reduction in levels

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortDarunavir

Contraindicated - significant reduction in levels

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortLopinavir

Contraindicated - significant reduction in levels

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortIrinotecan

Reduces active metabolite levels 50%, treatment failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortImatinib

Reduces imatinib levels 30-45%, cancer treatment failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortDocetaxel

Reduces levels, treatment failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortPaclitaxel

Reduces levels, treatment failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortVincristine

Reduces levels, treatment failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortEtoposide

Reduces levels, treatment failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortClopidogrel

Complex interaction - may increase active metabolite

Why: CYP2C19 effects

Known interaction

Avoid

St. John's WortSimvastatin

Reduces statin levels significantly

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortAtorvastatin

Reduces statin levels

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortNifedipine

Reduces calcium channel blocker levels

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortVerapamil

Reduces verapamil levels

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortDiltiazem

Reduces diltiazem levels

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortAmiodarone

Reduces amiodarone levels

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortSertraline (Zoloft)

Serotonin syndrome risk - AVOID

Why: Additive serotonergic effects

Known interaction

Avoid

St. John's WortFluoxetine (Prozac)

Serotonin syndrome risk - AVOID

Why: Additive serotonergic effects

Known interaction

Avoid

St. John's WortParoxetine (Paxil)

Serotonin syndrome risk - AVOID

Why: Additive serotonergic effects

Known interaction

Avoid

St. John's WortCitalopram (Celexa)

Serotonin syndrome risk - AVOID

Why: Additive serotonergic effects

Known interaction

Avoid

St. John's WortEscitalopram (Lexapro)

Serotonin syndrome risk - AVOID

Why: Additive serotonergic effects

Known interaction

Avoid

St. John's WortVenlafaxine (Effexor)

Serotonin syndrome risk - AVOID

Why: Additive serotonergic effects

Known interaction

Avoid

St. John's WortDuloxetine (Cymbalta)

Serotonin syndrome risk - AVOID

Why: Additive serotonergic effects

Known interaction

Avoid

St. John's WortMAOIs

Serotonin syndrome risk - CONTRAINDICATED

Why: Additive serotonergic effects

Known interaction

Avoid

St. John's WortTrazodone

Serotonin syndrome risk

Why: Additive serotonergic effects

Known interaction

Avoid

St. John's WortTramadol

Serotonin syndrome risk + reduced efficacy

Why: CYP3A4 + serotonin

Known interaction

Avoid

St. John's WortEthinyl estradiol

Breakthrough bleeding, contraceptive failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortNorethindrone

Reduced efficacy, contraceptive failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortLevonorgestrel

Reduced efficacy, contraceptive failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortDesogestrel

Reduced efficacy, contraceptive failure

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortCombined oral contraceptives

Breakthrough bleeding, unintended pregnancy

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortAlprazolam (Xanax)

Reduces alprazolam levels 50%

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortMidazolam

Reduces midazolam levels significantly

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortTriazolam

Reduces triazolam levels

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortMethadone

Reduces methadone levels, withdrawal symptoms

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortOxycodone

Reduces oxycodone efficacy

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortFentanyl

Reduces fentanyl levels

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortMycophenolate

Reduces levels, rejection risk

Why: UGT induction

Known interaction

Avoid

St. John's WortPhenytoin

Complex interaction - monitoring required

Why: CYP induction

Known interaction

Avoid

St. John's WortCarbamazepine

Complex interaction - monitoring required

Why: CYP induction

Known interaction

Avoid

St. John's WortPhenobarbital

Additive enzyme induction

Why: CYP induction

Known interaction

Avoid

St. John's WortDabigatran

Reduces dabigatran levels

Why: P-glycoprotein induction

Known interaction

Avoid

St. John's WortRivaroxaban

Reduces rivaroxaban levels

Why: CYP3A4 + P-gp induction

Known interaction

Avoid

St. John's WortApixaban

Reduces apixaban levels

Why: CYP3A4 + P-gp induction

Known interaction

Avoid

St. John's WortClozapine

Reduces clozapine levels

Why: CYP1A2 induction

Known interaction

Avoid

St. John's WortQuetiapine

Reduces quetiapine levels significantly

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortAripiprazole

Reduces aripiprazole levels

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortItraconazole

Reduced itraconazole levels significantly

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortVoriconazole

Reduced voriconazole levels

Why: CYP3A4 induction

Known interaction

Avoid

St. John's WortSumatriptan

Serotonin syndrome risk

Why: Additive serotonergic effects

Known interaction

Avoid

St. John's WortRizatriptan

Serotonin syndrome risk

Why: Additive serotonergic effects

Known interaction

Avoid

St. John's WortEletriptan

Serotonin syndrome risk

Why: Additive serotonergic effects

Known interaction

Avoid

St. John's WortTheophylline

Reduces theophylline levels

Why: CYP1A2 induction

Known interaction

Caution

17 · Combine carefully — read the note

Caution

St. John's WortZolpidem (Ambien)

May reduce zolpidem efficacy

Why: CYP3A4 induction

Known interaction

Caution

St. John's WortCodeine

Complex - may alter codeine metabolism

Why: CYP2D6 effects

Known interaction

Caution

St. John's WortPrednisone

May reduce corticosteroid levels

Why: CYP3A4 induction

Known interaction

Caution

St. John's WortOlanzapine

May reduce olanzapine levels

Why: CYP1A2 induction

Known interaction

Caution

St. John's WortErythromycin

Reduced erythromycin levels

Why: CYP3A4 induction

Known interaction

Caution

St. John's WortClarithromycin

Reduced clarithromycin levels

Why: CYP3A4 induction

Known interaction

Caution

St. John's WortOmeprazole

Reduced omeprazole levels

Why: CYP2C19 induction

Known interaction

Caution

St. John's WortEsomeprazole

Reduced esomeprazole levels

Why: CYP2C19 induction

Known interaction

Caution

St. John's WortFinasteride

May reduce finasteride levels

Why: CYP3A4 induction

Known interaction

Caution

St. John's WortSildenafil (Viagra)

Reduces sildenafil levels

Why: CYP3A4 induction

Known interaction

Caution

St. John's WortTadalafil (Cialis)

Reduces tadalafil levels

Why: CYP3A4 induction

Known interaction

Caution

St. John's WortBuspirone

Reduced buspirone efficacy

Why: CYP3A4 induction

Known interaction

Caution

St. John's WortBirth control (reduces effectiveness!)

St. John's Wort: Birth control (reduces effectiveness!)

Known interaction

Caution

St. John's WortSSRIs

St. John's Wort: SSRIs

Known interaction

Caution

St. John's WortBlood thinners

St. John's Wort: Blood thinners

Known interaction

Caution

St. John's WortHIV meds

St. John's Wort: HIV meds

Known interaction

Caution

St. John's WortMany others

St. John's Wort: Many others

Known interaction

Not medical advice. This tool surfaces well-established and known interactions from our reference data and curated rules. It is not exhaustive, can’t see your full health picture, and an absence of findings does not mean a combination is safe. Always consult a doctor or pharmacist about your supplements and medications.