Drug & supplement interaction

Jequirity + Levonorgestrel

Levonorgestrel brand names: Plan B, Mirena, Levonelle One Step, Levonelle 1500, Norgeston, and others.

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

Jequirity has a minor interaction with Levonorgestrel. In vitro research shows that jequirity extract inhibits CYP3A4 enzymes.

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

Jequirity and Levonorgestrel

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

Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Levonorgestrel

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

In vitro research shows that jequirity extract inhibits CYP3A4 enzymes. Theoretically, taking jequirity may inhibit the metabolism of CYP3A4 substrates.
Severity Minor Likelihood Unlikely Evidence D

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

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

First things first: jequirity is genuinely dangerous and should never be taken as a supplement. Its seeds contain abrin, a potent toxin similar to ricin, so this isn't something I'd want anyone near in the first place.

As for the interaction itself, your body uses an enzyme called CYP3A4 to help clear levonorgestrel (Plan B and similar). In a test tube, jequirity extract appears to slow that enzyme down, which in theory could let levonorgestrel build up a bit and make effects like nausea, headache, breast tenderness, or spotting slightly more likely. Keep in mind this is only lab-based, theoretical evidence, rated minor and unlikely. It is not a prodrug, so its effect wouldn't be weakened. Please don't use jequirity, and check with your pharmacist or doctor with any questions.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Ai C, Miao X, Wang L, He J. Discovery and Activity Evaluation of the Inhibitory Effect of Four Kinds Traditional Chinese Medicine Extracts on the CYP3A4 Enzyme. Comb Chem High Throughput Screen 2022.

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

Jequirity Also Interacts With Other Medications

Jequirity has 208 moderate, 602 minor known drug interactions in our database — the Levonorgestrel one above is one of them. If you take anything else, check it against the full list below.

Moderate 208 Minor 602 No known interaction 2,020 (incl. Levonorgestrel)
Taking anything else?

Check Another of Your Medications Against Jequirity

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

From our Q&A

Questions About Jequirity or Levonorgestrel

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

This page covers Jequirity only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Levonorgestrel page lists 191 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Grapefruit (major), Siberian Cocklebur (major) and St. John's Wort (major).

By severity: 6 major · 142 moderate · 43 minor.

From our pharmacist’s overview on the Levonorgestrel page

“St. John's wort tops my worry list for anyone using levonorgestrel (Plan B, Mirena, and other birth control).”

Reviewed by 2 · Jul 18, 2026

Open the Levonorgestrel interaction page

How much people look this up

Where Jequirity and Levonorgestrel 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 Jequirity
Steady interest

#1,178 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Levonorgestrel
Top 25%

#407 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 Jequirity

What is Jequirity?

Jequirity
  • Asthma and cough
  • Fever
  • Sore throat and bronchitis
  • Liver complaints (hepatitis)
  • Constipation
  • Traditional infectious-disease remedies

Jequirity (Abrus precatorius) is a tropical plant whose bright red, black-tipped seeds contain abrin, one of the most toxic plant proteins known. Despite a long history in traditional medicine, the seeds are dangerously poisonous and there is no reliable evidence that it is safe or effective. It should not be used as a supplement or medicine.

Read the full Jequirity monograph & all interactions
Medication

About Levonorgestrel

What Is Levonorgestrel Used For?

Brand names: Plan B, Mirena, Levonelle One Step, Levonelle 1500, Norgeston, Skyla, Liletta, Kyleena

Levonorgestrel is used in two very different ways depending on the product. As an intrauterine system (IUS), Mirena and Liletta prevent pregnancy for up to 8 years and also treat heavy menstrual bleeding for up to 5 years in people who choose intrauterine contraception. Kyleena prevents pregnancy for up to 5 years, and Skyla prevents pregnancy for up to 3 years — neither Kyleena nor Skyla is indicated for heavy menstrual bleeding.

As an oral tablet, products such as AfterPill, AfterPlan, Amazon Basic Care Levonorgestrel, Econ Morning After, Emergency Contraceptive, and Empowered Choice are used as emergency (backup) contraception to reduce the chance of pregnancy after unprotected sex or contraceptive failure. The oral tablet is not intended for routine birth control.

See full Levonorgestrel drug information
Keep checking

Other Drugs & Jequirity

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

0Major
208Moderate
602Minor
2,019No known interaction
208 Moderate 602 Minor 2,019 No interaction
Moderate

208 interactions

Showing 60 of 208 moderate interactions — see all 208 on the Jequirity page.

Minor

602 interactions

Showing 60 of 602 minor interactions — see all 602 on the Jequirity page.

No interaction 2,019 drugs checked — show the list

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

Showing the 60 most looked-up of 2,019 medications checked with no known interaction — see the full Jequirity list.

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

Can you take Jequirity with Levonorgestrel?
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 Jequirity and Levonorgestrel 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 Levonorgestrel and Jequirity?

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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.