Drug & supplement interaction

Jalap + Phenolphthalein

Phenolphthalein brand names: Modane, Evac-Q-Tab, Modane Mild.

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

Jalap has a major interaction with Phenolphthalein. Jalap has stimulant laxative effects. Concomitant use of jalap with other laxatives may lead to electrolyte and fluid depletion.

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

Jalap and Phenolphthalein

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

Major

STIMULANT LAXATIVES

Why this applies to Phenolphthalein

Phenolphthalein falls under STIMULANT LAXATIVES — the group Jalap interacts with.

Jalap has stimulant laxative effects. Concomitant use of jalap with other laxatives may lead to electrolyte and fluid depletion.
Severity Major 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

Here's the thing about pairing these two: both jalap and phenolphthalein are stimulant laxatives. They each work the same basic way, by irritating the lining of your gut and forcing the bowel to squeeze hard and empty out. So you're not getting two different effects, you're doubling up on the same aggressive one.

When you stack them, the worry is too much of a good thing: heavy diarrhea, belly cramping, and watery stools that can leave you dehydrated and low on important salts like potassium. That can show up as weakness, dizziness, or an irregular heartbeat. This caution is based on how these drugs work rather than hard studies, but the logic is sound. Please don't combine them on your own. Check with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 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

Jalap Also Interacts With Other Medications

Jalap has 20 major, 78 moderate, 1 minor known drug interactions in our database — the Phenolphthalein one above is one of them. If you take anything else, check it against the full list below.

Major 20 Moderate 78 Minor 1 No known interaction 2,731 (incl. Phenolphthalein)
Taking anything else?

Check Another of Your Medications Against Jalap

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

Everything else you take

See Every Supplement That Interacts With Phenolphthalein

This page covers Jalap only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phenolphthalein page lists 46 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Oleander (major), Alder Buckthorn (moderate), Aloe (moderate) and Black Hellebore (moderate).

By severity: 3 major · 34 moderate · 9 minor.

From our pharmacist’s overview on the Phenolphthalein page

“Phenolphthalein is a stimulant laxative itself, and that is the heart of the problem with these combinations. Most of the herbs on file, jalap being one, act the same way, so pairing them can drain fluid and potassium quickly.”

Reviewed by 2 · Jul 18, 2026

Open the Phenolphthalein interaction page

One more smart check

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

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

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

29 days ago today
Medication Phenolphthalein
Top half

#1,093 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 Jalap

What is Jalap?

  • Constipation
  • Strong laxative ('purgative') effect
  • Traditional remedy to 'clear out' the bowels
  • Historical use in folk medicine

Jalap is a powerful traditional laxative made from the root of a Mexican morning-glory plant. It is rarely used today because it can cause violent diarrhea, cramping, and dehydration, and safer laxatives are available. It is not recommended for routine self-treatment, and pregnant or breastfeeding people should avoid it.

Read the full Jalap monograph & all interactions
Keep checking

Other Drugs & Jalap

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

20Major
78Moderate
1Minor
2,730No known interaction
20 Major 78 Moderate 1 Minor 2,730 No interaction
Major

20 interactions

Moderate

78 interactions

Showing 60 of 78 moderate interactions — see all 78 on the Jalap page.

Minor

1 interaction

No interaction 2,730 drugs checked — show the list

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

Showing the 60 most looked-up of 2,730 medications checked with no known interaction — see the full Jalap list.

See the full Jalap interactions page
See every supplement checked against Phenolphthalein, 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
Jalap monograph › Uses, safety, and every drug interaction in one place Phenolphthalein supplement interactions › Every supplement checked against Phenolphthalein, 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 Jalap and Phenolphthalein Together: Common Questions

Can you take Jalap with Phenolphthalein?
This is rated a major interaction, so the combination is best avoided unless your doctor or pharmacist has specifically told you otherwise. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Jalap and Phenolphthalein interaction?
We rate it Major. This is a clinically significant combination that is generally best avoided, or used only under the direct supervision of your physician or pharmacist.

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

Still Have a Question About Phenolphthalein and Jalap?

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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.