Drug & supplement interaction

Ashitaba + Olanzapine

Olanzapine brand name: Zyprexa.

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

Ashitaba has a moderate interaction with Olanzapine. In vitro research shows that ashitaba extract inhibits cytochrome P450 (CYP) 1A2.

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

Ashitaba and Olanzapine

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

Moderate

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

Why this applies to Olanzapine

Olanzapine falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES — the group Ashitaba interacts with.

In vitro research shows that ashitaba extract inhibits cytochrome P450 (CYP) 1A2. Theoretically, concomitant use of ashitaba with CYP1A2 substrates might decrease the clearance of these substrates and increase the risk for adverse effects. However, this interaction has yet to be reported in humans. Until more is known, use with caution.
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 gist for Zyprexa. Your liver uses an enzyme called CYP1A2 to break down olanzapine and clear it out. In test-tube studies, ashitaba seems to slow that same enzyme down. If that holds true in people, your body might clear olanzapine a little more slowly, letting levels creep up. That could mean stronger side effects like drowsiness, dizziness, weight gain, or feeling unusually sluggish.

The honest truth: this is only a theory based on lab work, and it has never actually been reported in real patients. Eating ashitaba as a vegetable is unlikely to be a problem; concentrated supplements are the bigger question mark. Don't change your olanzapine on your own. Just give your pharmacist or doctor a heads-up before adding ashitaba.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Kwon D, Yoon S, Carter O, Bailey GS, Dashwood RH. Antioxidant and antigenotoxic activities of Angelica keiskei, Oenanthe javanica and Brassica oleracea in the Salmonella mutagenicity assay and in HCT116 human colon cancer cells. Biofactors. 2006;26(4):231

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

Ashitaba Also Interacts With Other Medications

Ashitaba has 185 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 185 No known interaction 2,645 (incl. Olanzapine)
Taking anything else?

Check Another of Your Medications Against Ashitaba

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

From our Q&A

Questions About Ashitaba 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 Ashitaba 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 Ashitaba 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

One more smart check

Taking Ashitaba as Part of a Dietary Supplement Product? Check It for Interactions

We hold 41 real supplement products containing Ashitaba, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Ashitaba. Your product may carry other ingredients that interact with Olanzapine too, on top of Ashitaba — 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 Ashitaba 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 Ashitaba
Top half

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

29 days ago today
Medication Olanzapine
Top 25%

#291 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 Ashitaba

What is Ashitaba?

Ashitaba
  • General wellness and longevity
  • Antioxidant support
  • Heart and cholesterol health
  • Digestive and stomach support
  • Anti-inflammatory

Ashitaba is a leafy plant from Japan that is eaten as a vegetable and taken as a supplement for general health, antioxidant, and heart benefits. Most of the supporting research comes from laboratory and animal studies, so its real benefits in people are still uncertain. It appears generally well tolerated as a food, but talk to your pharmacist or doctor before using concentrated supplements.

Read the full Ashitaba 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 & Ashitaba

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

0Major
185Moderate
0Minor
2,644No known interaction
185 Moderate 2,644 No interaction
Moderate

185 interactions

Showing 60 of 185 moderate interactions — see all 185 on the Ashitaba page.

No interaction 2,644 drugs checked — show the list

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

Showing the 60 most looked-up of 2,644 medications checked with no known interaction — see the full Ashitaba list.

See the full Ashitaba 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
Ashitaba 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 Ashitaba and Olanzapine Together: Common Questions

Can you take Ashitaba 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 Ashitaba 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 Ashitaba?

Our pharmacists answer your medication & supplement questions — free.

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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.