Drug & supplement interaction

St. John's Wort + Methylphenidate

Methylphenidate brand names: Ritalin, Ritalin-SR, Concerta, Methylin, Metadate, and others.

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

Methylphenidate falls into 2 drug categories that St. John's Wort can interact with; the most serious is rated moderate. Theoretically, St. John's wort might inhibit reuptake and increase levels of serotonin, resulting in additive effects with serotonergic drugs.

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

St. John's Wort and Methylphenidate

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

Why Are There 2 Interactions?

St. John's Wort interacts with whole categories of medication. Methylphenidate falls into 2 of those categories, so it can interact with St. John's Wort in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

SEROTONERGIC DRUGS

1 of 2

Why this applies to Methylphenidate

Methylphenidate falls under SEROTONERGIC DRUGS — the group St. John's Wort interacts with.

Theoretically, St. John's wort might inhibit reuptake and increase levels of serotonin, resulting in additive effects with serotonergic drugs.
Concomitant use of serotonergic drugs with St. John's wort can lead to increased adverse effects and increase the risk of serotonergic side effects, including serotonin syndrome and cerebral vasoconstriction disorders.
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 thing about pairing St. John's wort with methylphenidate (Ritalin, Concerta). St. John's wort can nudge up serotonin in the brain, and methylphenidate is a stimulant that also raises certain brain chemicals. Stacked together, the worry is too much serotonin activity, which can cause symptoms like agitation, a racing heart, sweating, shakiness, high blood pressure, or in rare cases a serious reaction called serotonin syndrome.

I'll be honest with you though, this caution is mostly theoretical, based on how each one works rather than a long list of real-world cases. So it's not a reason to panic, but it is worth a quick conversation. Please check with your pharmacist or doctor before combining them, and don't stop either one on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Miller LG. Herbal Medicinals: Selected clinical considerations focusing on known or potential drug-herb interactions. Arch Intern Med 1998;158:2200-11.
  2. Gordon JB. SSRIs and St. John's Wort: possible toxicity? Am Fam Physician 1998;57:950, 953.
  3. Beckman SE, Sommi RW, Switzer J. Consumer use of St. John's wort: A survey of effectiveness, safety, and tolerability. Pharmacotherapy 2000;20:568-74.
  4. Singhal AB, Caviness VS, Begleiter AF, et al. Cerebral vasoconstriction and stroke after use of serotonergic drugs. Neurology 2002;58:130-3. PubMed
  5. Sarris J, Ravindran A, Yatham LN, et al. Clinician guidelines for the treatment of psychiatric disorders with nutraceuticals and phytoceuticals: The World Federation of Societies of Biological Psychiatry (WFSBP) and Canadian Network for Mood and Anxiety T
Minor

METHYLPHENIDATE (Concerta, others)

2 of 2
St. John's wort might reduce the levels and clinical effects of methylphenidate.
St. John's wort might decrease the effectiveness of methylphenidate. In one report, an adult male, stabilized on methylphenidate for attention deficit-hyperactivity disorder (ADHD), experienced increased attention problems and ADHD symptoms after taking St. John's wort 600 mg daily for 4 months. ADHD symptoms improved when St. John's wort was discontinued. The mechanism of this interaction is unknown.
Severity Minor 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 short version for folks taking methylphenidate (Ritalin, Concerta, and similar) for ADHD: mixing in St. John's wort may quietly chip away at how well your stimulant works. This isn't about the drug building up to dangerous levels. If anything, the concern runs the other way, with the herb possibly lowering the effect.

I want to be honest about how thin the evidence is, though. It really comes down to a single case report, where one man noticed his focus slipping and his ADHD symptoms creeping back after months on St. John's wort, then improving once he stopped. We don't even know the mechanism. So this is a minor, anecdotal flag, not a hard rule. If you're considering St. John's wort, just loop in your pharmacist or doctor first so they can keep an eye on how your medication is working.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Niederhofer H. St. John's wort may diminish methylphenidate's efficacy in treating patients suffering from attention deficit hyperactivity disorder. Med Hypotheses 2007;68:1189. 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

St. John's Wort Also Interacts With Other Medications

St. John's Wort has 755 major, 387 moderate known drug interactions in our database — the Methylphenidate one above is among them. If you take anything else, check it against the full list below.

Major 755 Moderate 387 No known interaction 1,688 (incl. Methylphenidate)
Taking anything else?

Check Another of Your Medications Against St. John's Wort

Covers the 2,830 medications we’ve checked against St. John's Wort. Pick one to open its full report.

From our Q&A

Questions About St. John's Wort or Methylphenidate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers St. John's Wort or Methylphenidate, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Methylphenidate

This page covers St. John's Wort only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Methylphenidate page lists 85 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Ephedra (major), Lithium (major), Peyote (major) and Rauvolfia Vomitoria (major).

By severity: 6 major · 64 moderate · 15 minor.

From our pharmacist’s overview on the Methylphenidate page

“Methylphenidate (Ritalin, Concerta, Metadate) is itself a stimulant, and that one fact shapes most of this list. The largest cluster of interacting supplements adds a second stimulant on top of it, from ephedra and its relatives to everyday caffeine sources like coffee and green tea, which can push heart rate and blood pressure higher…”

Reviewed by 2 · Jul 18, 2026

Open the Methylphenidate interaction page

One more smart check

Taking St. John's Wort as Part of a Dietary Supplement Product? Check It for Interactions

We hold 1,159 real supplement products containing St. John's Wort, each one broken down to its full ingredient list — and combination products often carry several ingredients besides St. John's Wort. Your product may carry other ingredients that interact with Methylphenidate too, on top of St. John's Wort — 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 St. John's Wort and Methylphenidate 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 St. John's Wort
Top 25%

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

29 days ago today
Medication Methylphenidate
Top 10

#8 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 St. John's Wort

What is St. John's Wort?

St. John's Wort
  • Mild to moderate depression
  • Anxiety and stress
  • Sleep problems
  • Menopausal symptoms
  • Wound healing (topical)

St. John's wort is a well-studied herb most often used for mild to moderate depression, and some research suggests it may help with this. However, it has many serious interactions with prescription medicines and is not safe for everyone, so always talk to your pharmacist or doctor before taking it.

Read the full St. John's Wort monograph & all interactions
Medication

About Methylphenidate

What Is Methylphenidate Used For?

Brand names: Ritalin, Ritalin-SR, Concerta, Methylin, Metadate, Metadate CD, Methylin ER, Ritalin LA, Aptensio XR, Quillivant Xr, Cotempla XR-ODT, Jornay PM, Relexxii

Methylphenidate is used to treat Attention Deficit Hyperactivity Disorder (ADHD) — a condition marked by inattention, hyperactivity, and impulsivity that interferes with daily life at home, school, or work. It is available in many forms (oral tablets, capsules, liquid, chewable tablets, orally disintegrating tablets, and a skin patch), and each formulation has its own specific approved age range.

Some oral extended-release tablet formulations are also approved to treat narcolepsy (a sleep disorder causing excessive daytime sleepiness). The oral solution and chewable tablets are indicated for children with ADHD as part of a broader treatment program that may include counseling and educational support. Not every formulation is approved for every age group or condition — check with your prescriber or pharmacist for the specifics of your product.

See full Methylphenidate drug information
Keep checking

Other Drugs & St. John's Wort

Browse every other medication we’ve checked against St. John's Wort — both the ones with a known interaction and the ones without. Select any drug for the full detail.

755Major
387Moderate
0Minor
1,687No known interaction
755 Major 387 Moderate 1,687 No interaction
Major

755 interactions

Showing 60 of 755 major interactions — see all 755 on the St. John's Wort page.

Moderate

387 interactions

Showing 60 of 387 moderate interactions — see all 387 on the St. John's Wort page.

No interaction 1,687 drugs checked — show the list

We also checked St. John's Wort against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 1,687 medications checked with no known interaction — see the full St. John's Wort list.

See the full St. John's Wort interactions page
See every supplement checked against Methylphenidate, 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
St. John's Wort monograph › Uses, safety, and every drug interaction in one place Methylphenidate supplement interactions › Every supplement checked against Methylphenidate, ranked by severity Methylphenidate drug information › The full plain-English guide to this medication 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 St. John's Wort and Methylphenidate Together: Common Questions

Can you take St. John's Wort with Methylphenidate?
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 St. John's Wort and Methylphenidate?
Methylphenidate belongs to more than one drug category, and St. John's Wort 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 St. John's Wort and Methylphenidate 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

Still Have a Question About Methylphenidate and St. John's Wort?

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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.