Drug & supplement interaction

Cascara Sagrada + Sildenafil

Sildenafil brand name: Revatio.

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

Cascara Sagrada has a minor interaction with Sildenafil. Theoretically, cascara sagrada might decrease the effects of CYP3A4 substrates.

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

Cascara Sagrada and Sildenafil

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

Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Sildenafil

Sildenafil falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Cascara Sagrada interacts with.

Theoretically, cascara sagrada might decrease the effects of CYP3A4 substrates.
In vitro research suggests that cascara sagrada can induce CYP3A4 enzymes, albeit to a much lower degree than rifampin, a known CYP3A4 inducer.
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 short version: your liver uses an enzyme called CYP3A4 to clear sildenafil out of your body. Lab studies hint that cascara sagrada might gently speed that enzyme up. If that happened, your body could break down sildenafil a little faster, which in theory might make it work a bit less. For erectile dysfunction that could mean a weaker response, and for pulmonary hypertension (Revatio) it could mean slightly less benefit.

Honestly though, I wouldn't lose sleep over this one. The evidence is only from test-tube research, the effect was much weaker than known enzyme boosters, and it's rated minor. Short, occasional cascara use is unlikely to cause a real problem. Still, if you take sildenafil regularly, it's worth a quick chat with your pharmacist or doctor before starting cascara.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Mazzari ALDA, Lacerda MG, Milton FA, et al. In vitro effects of European and Latin-American medicinal plants in CYP3A4 gene expression, glutathione levels, and P-glycoprotein activity. Front Pharmacol 2022;13:826395. 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

Cascara Sagrada Also Interacts With Other Medications

Cascara Sagrada has 122 moderate, 622 minor known drug interactions in our database — the Sildenafil one above is one of them. If you take anything else, check it against the full list below.

Moderate 122 Minor 622 No known interaction 2,086 (incl. Sildenafil)
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.

From our Q&A

Questions About Cascara Sagrada or Sildenafil

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

This page covers Cascara Sagrada only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Sildenafil page lists 160 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Mistletoe (major), Grapefruit (major), Hawthorn (major) and St. John's Wort (major).

By severity: 5 major · 114 moderate · 41 minor.

From our pharmacist’s overview on the Sildenafil page

“Sildenafil relaxes blood vessels, whether prescribed as Revatio for pulmonary hypertension or as Viagra, and that blood-pressure-lowering action makes this list one to treat with genuine care. Of the 160 supplement and herbal ingredients on file, five carry a major rating, and those deserve understanding first.”

Reviewed by 2 · Jul 18, 2026

Open the Sildenafil 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 Sildenafil 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 Sildenafil 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%

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

29 days ago today
Medication Sildenafil
Top 25%

#451 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
Medication

About Sildenafil

What Is Sildenafil Used For?

Brand name: Revatio

Sildenafil treats two distinct conditions depending on the product. Viagra (tablet) and Vybrique (dissolving oral film) are approved for erectile dysfunction (ED) — difficulty getting or keeping an erection. Generic sildenafil tablets and oral film are also approved for ED.

Revatio and several generic sildenafil products (tablets, oral suspension, and injection) are used for pulmonary arterial hypertension (PAH) — high blood pressure in the arteries of the lungs — in adults to improve exercise ability and slow the disease from getting worse. Revatio oral suspension and injection are also approved for PAH in children ages 1 to 17.

See full Sildenafil drug information
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
122Moderate
622Minor
2,085No known interaction
122 Moderate 622 Minor 2,085 No interaction
Moderate

122 interactions

Showing 60 of 122 moderate interactions — see all 122 on the Cascara Sagrada page.

Minor

622 interactions

Showing 60 of 622 minor interactions — see all 622 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 Sildenafil, 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 Sildenafil supplement interactions › Every supplement checked against Sildenafil, ranked by severity Sildenafil 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 Cascara Sagrada and Sildenafil Together: Common Questions

Can you take Cascara Sagrada with Sildenafil?
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 Cascara Sagrada and Sildenafil 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 Sildenafil 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.