Drug & supplement interaction

European Mandrake + Olanzapine

Olanzapine brand name: Zyprexa.

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

European Mandrake has a moderate interaction with Olanzapine. Theoretically, concurrent use might increase absorption of some drugs because of inhibited gastrointestinal (GI) motility caused by European mandrake.

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

European Mandrake and Olanzapine

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

Moderate

ORAL DRUGS

Why this applies to Olanzapine

Olanzapine falls under ORAL DRUGS — the group European Mandrake interacts with.

Theoretically, concurrent use might increase absorption of some drugs because of inhibited gastrointestinal (GI) motility caused by European mandrake.
Severity Moderate Likelihood Probable Evidence D

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..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

First things first: European mandrake is genuinely toxic, and I would not recommend taking it at all. But here is the idea behind this interaction. Mandrake's tropane alkaloids slow down how fast your gut moves. When your stomach and intestines empty more slowly, a pill like olanzapine can sit there longer and get absorbed a bit more fully, which in theory could raise how much ends up in your body.

If that happened, you might feel more of olanzapine's usual effects, like heavy drowsiness, dizziness, low blood pressure, or a very dry mouth (something mandrake already causes on its own). This is a theoretical concern based on how these chemicals behave, not proven cases. Please don't use mandrake, and check with your pharmacist or doctor about anything you take alongside olanzapine.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.

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

European Mandrake Also Interacts With Other Medications

European Mandrake has 2,041 moderate known drug interactions in our database — the Olanzapine one above is one of them. If you take anything else, check it against the full list below.

Moderate 2,041 No known interaction 789 (incl. Olanzapine)
Taking anything else?

Check Another of Your Medications Against European Mandrake

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

From our Q&A

Questions About European Mandrake or Olanzapine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers European Mandrake or Olanzapine, 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 Olanzapine

This page covers European Mandrake only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Olanzapine page lists 160 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Indian Snakeroot (major), Lithium (major), Rauvolfia Vomitoria (major) and 1,3-dmaa (moderate).

By severity: 4 major · 118 moderate · 38 minor.

From our pharmacist’s overview on the Olanzapine page

“Olanzapine (Zyprexa) is an antipsychotic prescribed for schizophrenia and bipolar disorder, and adding supplements to it warrants genuine care. Four of the 160 ingredients on file rate major, and those four deserve your attention before anything else: lithium supplements raise the risk of serotonin syndrome, activated charcoal can trap…”

Reviewed by 2 · Jul 18, 2026

Open the Olanzapine interaction page

How much people look this up

Where European Mandrake and Olanzapine 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 European Mandrake
Top 25%

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

29 days ago today
Medication Olanzapine
Top half

#753 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 European Mandrake

What is European Mandrake?

European Mandrake
  • Insomnia (traditional)
  • Pain relief (historical)
  • Anxiety or depression (folk use)
  • Gout and aches (traditional)
  • Sedation or anesthesia (historical)

European mandrake is a highly toxic plant from the nightshade family that was used in ancient and medieval times as a sedative and pain reliever. It contains powerful poisons that can cause serious harm or death, and there is no proof it safely treats any condition. We strongly recommend you do not consume mandrake in any form.

Read the full European Mandrake monograph & all interactions
Medication

About Olanzapine

What Is Olanzapine Used For?

Brand name: Zyprexa

Olanzapine treats schizophrenia and the manic or mixed episodes of bipolar I disorder in both adults and adolescents (ages 13–17). It can also be used alongside valproate or lithium to treat manic or mixed episodes in adults. When combined with fluoxetine, olanzapine tablets and orally disintegrating tablets are used to treat depressive episodes associated with bipolar I disorder and treatment-resistant depression in adults.

Olanzapine intramuscular injection (short-acting) is used by healthcare providers to quickly calm acute agitation in adults with schizophrenia or bipolar I mania. Zyprexa Relprevv — a separate, long-acting intramuscular formulation available only through a restricted program — is indicated specifically for the treatment of schizophrenia in adults.

See full Olanzapine drug information
Keep checking

Other Drugs & European Mandrake

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

0Major
2,041Moderate
0Minor
788No known interaction
2,041 Moderate 788 No interaction
Moderate

2,041 interactions

Showing 60 of 2,041 moderate interactions — see all 2,041 on the European Mandrake page.

No interaction 788 drugs checked — show the list

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

Showing the 60 most looked-up of 788 medications checked with no known interaction — see the full European Mandrake list.

See the full European Mandrake interactions page
See every supplement checked against Olanzapine, 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
European Mandrake monograph › Uses, safety, and every drug interaction in one place Olanzapine supplement interactions › Every supplement checked against Olanzapine, ranked by severity Olanzapine 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 European Mandrake and Olanzapine Together: Common Questions

Can you take European Mandrake with Olanzapine?
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 European Mandrake and Olanzapine 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 Olanzapine and European Mandrake?

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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.