Drug & supplement interaction

Ashwagandha + Busulfan

Busulfan brand names: Myleran, Busulfex.

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

Ashwagandha has a minor interaction with Busulfan. Theoretically, ashwagandha might decrease the levels and clinical effects of CYP3A4 substrates.

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

Ashwagandha and Busulfan

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

Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Busulfan

Busulfan falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Ashwagandha interacts with.

Theoretically, ashwagandha might decrease the levels and clinical effects of CYP3A4 substrates.
In vitro research shows that ashwagandha extract induces CYP3A4 enzymes.
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 theory with this pairing: lab studies hint that ashwagandha may speed up an enzyme called CYP3A4, which is one of the pathways that helps clear busulfan from your body. If that holds true in people, your body might break busulfan down a little faster, which could lower the amount in your blood and possibly make it less effective against the leukemia. Busulfan is not a prodrug, so faster clearance means weaker effect, not more.

I want to be honest about the strength of this: it comes only from test-tube research, not from human studies, so we really don't know if it matters in real life. But busulfan is a powerful chemo drug with very precise dosing, so don't add ashwagandha without first clearing it with your oncology team.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Haron MH, Dale O, Martin K, et al. Evaluation of the Herb-Drug Interaction Potential of Commonly Used Botanicals on the US Market with Regard to PXR- and AhR-Mediated Influences on CYP3A4 and CYP1A2. J Diet Suppl 2022. 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

Ashwagandha Also Interacts With Other Medications

Ashwagandha has 916 moderate, 455 minor known drug interactions in our database — the Busulfan one above is one of them. If you take anything else, check it against the full list below.

Moderate 916 Minor 455 No known interaction 1,459 (incl. Busulfan)
Taking anything else?

Check Another of Your Medications Against Ashwagandha

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

From our Q&A

Questions About Ashwagandha or Busulfan

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

This page covers Ashwagandha only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Busulfan page lists 148 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Acerola (moderate).

By severity: 3 major · 104 moderate · 41 minor.

Open the Busulfan interaction page

One more smart check

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

We hold 4,964 real supplement products containing Ashwagandha, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Ashwagandha. Your product may carry other ingredients that interact with Busulfan too, on top of Ashwagandha — 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 Ashwagandha and Busulfan 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 Ashwagandha
Top 5%

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

29 days ago today
Medication Busulfan
Top half

#1,337 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 Ashwagandha

What is Ashwagandha?

Ashwagandha
  • Stress and anxiety
  • Sleep problems
  • Fatigue and low energy
  • Athletic performance
  • General well-being (adaptogen)

Ashwagandha is an Ayurvedic herb most often taken to help with stress, anxiety, and sleep, and some small studies suggest it may help, though the evidence is still limited. It is generally well tolerated for short-term use in healthy adults, but it should be avoided in pregnancy and used cautiously by people with thyroid or liver problems. Talk with your pharmacist or doctor before starting it.

Read the full Ashwagandha monograph & all interactions
Medication

About Busulfan

What Is Busulfan Used For?

Brand names: Myleran, Busulfex

Busulfan is used to treat chronic myelogenous leukemia (CML), a cancer of the blood and bone marrow. The specific use depends on the form and product.

Myleran (oral tablet) is used for the palliative treatment of CML — meaning it helps control the disease and relieve symptoms. The intravenous injection forms (Busulfex and Busulfan Injection) are used in combination with another chemotherapy drug, cyclophosphamide, as a conditioning regimen to prepare the body before an allogeneic hematopoietic progenitor cell transplant (a bone marrow or stem cell transplant from a donor) for CML.

See full Busulfan drug information
Keep checking

Other Drugs & Ashwagandha

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

0Major
916Moderate
455Minor
1,458No known interaction
916 Moderate 455 Minor 1,458 No interaction
Moderate

916 interactions

Showing 60 of 916 moderate interactions — see all 916 on the Ashwagandha page.

Minor

455 interactions

Showing 60 of 455 minor interactions — see all 455 on the Ashwagandha page.

No interaction 1,458 drugs checked — show the list

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

Showing the 60 most looked-up of 1,458 medications checked with no known interaction — see the full Ashwagandha list.

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

Can you take Ashwagandha with Busulfan?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Ashwagandha and Busulfan interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Busulfan and Ashwagandha?

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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.