Drug & supplement interaction

Cascara Sagrada + Polythiazide

Polythiazide brand name: Renese.

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

Cascara Sagrada has a moderate interaction with Polythiazide. Theoretically, cascara sagrada might increase the risk of hypokalemia when taken with diuretic drugs.

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

Cascara Sagrada and Polythiazide

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

Moderate

DIURETIC DRUGS

Why this applies to Polythiazide

Polythiazide falls under DIURETIC DRUGS — the group Cascara Sagrada interacts with.

Theoretically, cascara sagrada might increase the risk of hypokalemia when taken with diuretic drugs.
Cascara sagrada has stimulant laxative effects, and long-term use has been associated with hypokalemia.
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 concern with pairing these two. Polythiazide (Renese) is a water pill that already nudges your body to dump potassium in the urine. Cascara sagrada, used as a stimulant laxative, can also push potassium out, mostly through the stool, especially if you use it for more than a few days. Stack the two and your potassium could dip lower than you'd want.

Low potassium can leave you feeling weak, crampy, tired, or give you an irregular or fluttering heartbeat. Now, this is a theoretical interaction based on how each one works, not a flood of case reports, so I don't want to alarm you. A one-time, short use is unlikely to be a big deal. Still, it's worth a quick chat with your pharmacist or doctor before combining them, and they may check your potassium.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  2. 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

Cascara Sagrada Also Interacts With Other Medications

Cascara Sagrada has 121 moderate, 623 minor known drug interactions in our database — the Polythiazide one above is one of them. If you take anything else, check it against the full list below.

Moderate 121 Minor 623 No known interaction 2,086 (incl. Polythiazide)
Taking anything else?

Check Another of Your Medications Against Cascara Sagrada

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

Everything else you take

See Every Supplement That Interacts With Polythiazide

This page covers Cascara Sagrada only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Polythiazide page lists 227 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Asarabacca (major) and Dolomite (major).

By severity: 10 major · 192 moderate · 25 minor.

From our pharmacist’s overview on the Polythiazide page

“Polythiazide (Renese) is a thiazide diuretic for high blood pressure, and this is a list I would treat with real care. Most entries either add to its blood-pressure-lowering and fluid-losing effects or deepen the potassium loss it already causes, which can leave someone dizzy or set the stage for heart rhythm trouble.”

Reviewed by 2 · Jul 18, 2026

Open the Polythiazide interaction page

One more smart check

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

We hold 849 real supplement products containing Cascara Sagrada, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cascara Sagrada. Your product may carry other ingredients that interact with Polythiazide too, on top of Cascara Sagrada — 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 Cascara Sagrada and Polythiazide 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 Cascara Sagrada
Top 25%

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

29 days ago today
Medication Polythiazide
Top half

#1,409 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 Cascara Sagrada

What is Cascara Sagrada?

Cascara Sagrada
  • Constipation
  • Bowel cleansing before procedures
  • Hemorrhoids
  • Traditional liver and gallbladder remedy

Cascara sagrada is a stimulant laxative made from the aged bark of a Pacific Northwest tree, used mainly for short-term relief of constipation. Because it can cause cramping, dehydration, and electrolyte problems—and was removed from over-the-counter laxative products in the U.S. due to safety concerns—it should only be used briefly, if at all, and with guidance from a pharmacist or doctor.

Read the full Cascara Sagrada monograph & all interactions
Keep checking

Other Drugs & Cascara Sagrada

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

0Major
121Moderate
623Minor
2,085No known interaction
121 Moderate 623 Minor 2,085 No interaction
Moderate

121 interactions

Showing 60 of 121 moderate interactions — see all 121 on the Cascara Sagrada page.

Minor

623 interactions

Showing 60 of 623 minor interactions — see all 623 on the Cascara Sagrada page.

No interaction 2,085 drugs checked — show the list

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

Showing the 60 most looked-up of 2,085 medications checked with no known interaction — see the full Cascara Sagrada list.

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

Can you take Cascara Sagrada with Polythiazide?
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 Cascara Sagrada and Polythiazide 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 Polythiazide and Cascara Sagrada?

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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.