Drug & supplement interaction

Neem + Erythromycin Ethylsuccinate

Erythromycin Ethylsuccinate brand names: E.E.S. 400, E.E.S. Chewable, Wyamycin S.

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

Erythromycin Ethylsuccinate falls into 2 drug categories that Neem can interact with; the most serious is rated moderate. Theoretically, neem leaf extract might increase the levels and clinical effects of P-glycoprotein substrates.

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

Neem and Erythromycin Ethylsuccinate

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

Why Are There 2 Interactions?

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

Moderate

P-GLYCOPROTEIN SUBSTRATES

1 of 2

Why this applies to Erythromycin Ethylsuccinate

Erythromycin Ethylsuccinate falls under P-GLYCOPROTEIN SUBSTRATES — the group Neem interacts with.

Theoretically, neem leaf extract might increase the levels and clinical effects of P-glycoprotein substrates.
In vitro research shows that neem leaf methanol extract inhibits renal P-glycoprotein transport activity. So far, this reaction has not been reported in humans.
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 simple version. Your body uses a tiny pump called P-glycoprotein to help move erythromycin out of cells and clear it along. In lab dishes, neem leaf extract seems to slow that pump down. If that same thing happened in people, a little more erythromycin could hang around in your system than usual, which might nudge up its typical side effects like nausea, stomach cramps, or diarrhea.

The honest part: this is only seen in test-tube and animal studies, never actually reported in real patients. So it's more of a theoretical heads-up than a proven problem. Concentrated neem capsules are more likely to matter than tiny amounts in toothpaste or skin products. If you want to use both, just check in with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Amaeze O, Marques ES, Wei W, et al. Evaluation of Nigerian Medicinal Plants Extract on Human P-glycoprotein and Cytochrome P450 Enzyme Induction: Implications for Herb-drug Interaction. Curr Drug Metab. 2021;22(14):1103-1113. PubMed
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 2

Erythromycin Ethylsuccinate also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, neem leaf extract might increase the levels and clinical effects of CYP3A4 substrates.
In vitro research shows that neem leaf methanol extract inhibits CYP3A4 enzymes. So far, this reaction has not been reported in humans.
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 simple version. Your body clears erythromycin partly through a liver enzyme called CYP3A4. In test-tube studies, neem leaf extract seems to slow that same enzyme down. If that happened in real life, erythromycin could build up a bit higher than usual, which might mean more of its typical side effects, things like nausea, stomach cramping, or diarrhea.

I want to be honest about how shaky this is, though. So far this has only been seen in lab dishes, never reported in actual people, so we really don't know if it matters at the doses you'd take. I wouldn't lose sleep over it, but since concentrated neem supplements are stronger than anything you'd get from food, just give your pharmacist or doctor a heads-up before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Amaeze O, Eng H, Horlbogen L, Varma MVS, Slitt A. Cytochrome P450 Enzyme Inhibition and Herb-Drug Interaction Potential of Medicinal Plant Extracts Used for Management of Diabetes in Nigeria. Eur J Drug Metab Pharmacokinet. 2021;46(3):437-450. 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

Neem Also Interacts With Other Medications

Neem has 1,012 moderate known drug interactions in our database — the Erythromycin Ethylsuccinate one above is among them. If you take anything else, check it against the full list below.

Moderate 1,012 No known interaction 1,818 (incl. Erythromycin Ethylsuccinate)
Taking anything else?

Check Another of Your Medications Against Neem

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

Everything else you take

See Every Supplement That Interacts With Erythromycin Ethylsuccinate

This page covers Neem only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Erythromycin Ethylsuccinate page lists 202 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 9 major · 153 moderate · 40 minor.

From our pharmacist’s overview on the Erythromycin Ethylsuccinate page

“Most people take erythromycin ethylsuccinate (E.E.S.) for a short course to clear an infection, often with a probiotic on the side. That does not make its 202 interacting ingredients low stakes; the nine rated major deserve a careful read first.”

Reviewed by 2 · Jul 18, 2026

Open the Erythromycin Ethylsuccinate interaction page

One more smart check

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

We hold 288 real supplement products containing Neem, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Neem. Your product may carry other ingredients that interact with Erythromycin Ethylsuccinate too, on top of Neem — 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 Neem and Erythromycin Ethylsuccinate 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 Neem
Top 25%

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

29 days ago today
Medication Erythromycin Ethylsuccinate
Steady interest

#1,998 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 Neem

What is Neem?

Neem
  • Skin conditions
  • Dental and gum health
  • Antimicrobial and antiparasitic
  • Digestive upset
  • Blood sugar support
  • Insect repellent/pesticide

Neem is a tree from India used for centuries in traditional medicine, especially for skin, dental, and antimicrobial purposes. Some small studies are promising for oral health and skin, but high-quality human evidence is limited for most uses. Neem oil and seed extracts can be toxic if swallowed, especially in children, so use with caution and talk to your pharmacist or doctor first.

Read the full Neem monograph & all interactions
Keep checking

Other Drugs & Neem

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

0Major
1,012Moderate
0Minor
1,817No known interaction
1,012 Moderate 1,817 No interaction
Moderate

1,012 interactions

Showing 60 of 1,012 moderate interactions — see all 1,012 on the Neem page.

No interaction 1,817 drugs checked — show the list

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

Showing the 60 most looked-up of 1,817 medications checked with no known interaction — see the full Neem list.

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

Can you take Neem with Erythromycin Ethylsuccinate?
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 Neem and Erythromycin Ethylsuccinate?
Erythromycin Ethylsuccinate belongs to more than one drug category, and Neem 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 Neem and Erythromycin Ethylsuccinate 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

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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.