Drug & supplement interaction

Cascara Sagrada + 6-Mercaptopurine

6-Mercaptopurine brand name: Purinethol.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Cascara Sagrada and 6-Mercaptopurine in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Cascara Sagrada and 6-Mercaptopurine

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between 6-Mercaptopurine and Cascara Sagrada in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Cascara Sagrada safety at a glance

Cascara Sagrada overall Use caution It may help short-term constipation but carries real risks, especially with long-term use.
Pregnancy Avoid Stimulant laxatives like cascara are generally not recommended during pregnancy.
Breastfeeding Possibly Unsafe When used orally. Cascara sagrada is excreted into breast milk and might cause diarrhea. Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining 6-Mercaptopurine and Cascara Sagrada? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for 6-Mercaptopurine

Interactions in our licensed database are recorded against drug classes, not just single drug names. 6-Mercaptopurine is filed under 3 classifications — immunosuppressants, hepatotoxic drugs, oral drugs. Cascara Sagrada has documented interactions with 6 drug classes — the most serious being corticosteroids (moderate), digoxin (lanoxin) (moderate) and diuretic drugs (moderate) — and none of 6-Mercaptopurine’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Cascara Sagrada Does Interact With Other Medications

Cascara Sagrada has 122 moderate, 623 minor known drug interactions in our database — 6-Mercaptopurine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 122 Minor 623 No known interaction 2,085 (incl. 6-Mercaptopurine)
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.

What to actually watch for

No Interaction Found — But Data Suggests Cascara Sagrada and 6-Mercaptopurine May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 2 of them are worth acting on rather than waiting out — marked below.

  • Raised blood pressure Worth acting on Additional detail

    Cascara Sagrada

    “There is some concern about potential liver problems with cascara sagrada. In some cases, cascara sagrada bark 750-1275 mg (containing approximately 21 mg cascaroside) daily in divided doses for three days resulted in cholestatic hepatitis, ascites, and portal hypertension. Symptoms resolved following discontinuation of cascara sagrada.”

    Cascara Sagrada · Natural Medicines adverse-effect record, reported in hepatitis.

    2 sources cited
    1. 6895. Nadir A, Reddy D, Van Thiel DH. Cascara-sagrada induced intrahepatic cholestasis causing portal hypertension: case report and review of herbal hepatotoxicity. Am J Gastroenterol 2000;95:3634-7. PubMed
    2. 92306. Nakasone ES, Tokeshi J. A serendipitous find: a case of cholangiocarcinoma identified incidentally after acute liver injury due to cascara sagrada ingestion. Hawaii J Med Public Health 2015;74(6):200-2.

    6-Mercaptopurine

    Listed in the ADVERSE REACTIONS section of the FDA label for 6-Mercaptopurine. Read the label on DailyMed ›

  • Liver problems Worth acting on Additional detail

    Cascara Sagrada

    “Orally, cascara sagrada seem to be well tolerated when used appropriately, short-term.

    Most Common Adverse Effects:

    Orally: Mild abdominal discomfort and cramps.

    Serious Adverse Effects (Rare):

    Orally: Hepatotoxicity. Fresh or improperly aged cascara sagrada bark can cause severe vomiting.”

    Cascara Sagrada · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    6-Mercaptopurine

    Listed in the ADVERSE REACTIONS section of the FDA label for 6-Mercaptopurine. Read the label on DailyMed ›

  • Vomiting reported in 4.3% of FDA reports for 6-Mercaptopurine Additional detail

    Cascara Sagrada

    “Orally, cascara sagrada can commonly cause mild abdominal discomfort, colic, and cramps (4). In some cases, chronic use can cause pseudomelanosis coli. Pseudomelanosis coli (pigment spots in intestinal mucosa) is believed to be harmless, usually reverses with discontinuation, and is not directly associated with an increased risk of developing colorectal adenoma or carcinoma.

    Fresh or improperly aged cascara sagrada b…”

    Cascara Sagrada · Natural Medicines adverse-effect record, reported in colorectal adenoma.

    4 sources cited
    1. 4. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
    2. 6138. Nusko G, Schneider B, Schneider I, et al. Anthranoid laxative use is not a risk factor for colorectal neoplasia: results of a prospective case control study. Gut 2000;46:651-5. PubMed
    3. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
    4. 92307. Cirillo C, Capasso R. Constipation and botanical medicines: an overview. Phytother Res 2015;29(10):1488-93. PubMed

    6-Mercaptopurine

    Listed in the ADVERSE REACTIONS section of the FDA label for 6-Mercaptopurine, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Reported for Cascara Sagrada but not commonly for 6-Mercaptopurine: stomach upset.

Effects for 6-Mercaptopurine come from the ADVERSE REACTIONS section of its FDA label; effects for Cascara Sagrada come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 17,242 voluntary FDA FAERS reports for 6-Mercaptopurine that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Cascara Sagrada in Pregnancy & Breastfeeding

Lactation Possibly Unsafe

When used orally. Cascara sagrada is excreted into breast milk and might cause diarrhea.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

Questions About Cascara Sagrada or 6-Mercaptopurine

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 6-Mercaptopurine, 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 6-Mercaptopurine

This page covers Cascara Sagrada only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the 6-Mercaptopurine page lists 106 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Siberian Cocklebur (major), Wine (major) and Active Hexose Correlated Compound (ahcc) (moderate).

By severity: 4 major · 92 moderate · 10 minor.

From our pharmacist’s overview on the 6-Mercaptopurine page

“6-Mercaptopurine (Purinethol) works by dialing down your immune system, whether for leukemia or inflammatory bowel disease, and that makes this a list to check with real care. The four major-rated entries come first.”

Reviewed by 2 · Jul 18, 2026

Open the 6-Mercaptopurine 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. Even though Cascara Sagrada itself has no known interaction with 6-Mercaptopurine, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Cascara Sagrada and 6-Mercaptopurine 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%

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

29 days ago today
Medication 6-Mercaptopurine
Steady interest

#1,651 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Cascara Sagrada reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Cascara Sagrada and 6-Mercaptopurine records this page draws on were last updated July 11, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
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.

Frangula purshiana · Rhamnaceae · Dried, aged bark · Capsules, tablets, dried bark, liquid extract, tea

An interaction check asks whether these two react with each other — it does not ask whether Cascara Sagrada is a good idea for someone in your situation. Here is what our Cascara Sagrada record says about it on its own.

Cascara Sagrada: dosing

There is no single official standardized dose for cascara sagrada supplements, and products vary in strength. The safest approach is to follow the directions on the product label and use the lowest amount that works.As a general rule, stimulant laxatives like cascara are meant for short-term use only—typically no more than about one week unless a doctor advises otherwise. Aged (cured) bark should always be used, never fresh bark.

From our Cascara Sagrada monograph — the full record covers uses, side effects and every documented interaction.

Read the full Cascara Sagrada monograph & all interactions
Medication

About Mercaptopurine

What Is Mercaptopurine Used For?

Brand name: Purinethol

Mercaptopurine — available as a tablet and as an oral suspension — is used to treat acute lymphoblastic leukemia (ALL), a type of blood cancer. It is given as part of a combination chemotherapy maintenance regimen, meaning it works alongside other cancer medicines to keep leukemia in remission.

Both the tablet form and the oral suspension form carry this indication for adult and pediatric patients. The oral suspension is particularly useful for patients who cannot swallow tablets.

See full Mercaptopurine 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
623Minor
2,084No known interaction
122 Moderate 623 Minor 2,084 No interaction
Moderate

122 interactions

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

Minor

623 interactions

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

No interaction 2,084 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 2,084 medications checked with no known interaction — see the full Cascara Sagrada list.

See the full Cascara Sagrada interactions page
See every supplement checked against 6-Mercaptopurine, ranked by severity
Evidence & sources

Cascara Sagrada References

The 9 references that drive our Cascara Sagrada monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
  2. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  3. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  4. Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
  5. Nusko G, Schneider B, Schneider I, et al. Anthranoid laxative use is not a risk factor for colorectal neoplasia: results of a prospective case control study. Gut 2000;46:651-5. PubMed
  6. Nadir A, Reddy D, Van Thiel DH. Cascara-sagrada induced intrahepatic cholestasis causing portal hypertension: case report and review of herbal hepatotoxicity. Am J Gastroenterol 2000;95:3634-7. PubMed
  7. Nakasone ES, Tokeshi J. A serendipitous find: a case of cholangiocarcinoma identified incidentally after acute liver injury due to cascara sagrada ingestion. Hawaii J Med Public Health 2015;74(6):200-2.
  8. Cirillo C, Capasso R. Constipation and botanical medicines: an overview. Phytother Res 2015;29(10):1488-93. PubMed
  9. 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

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Cascara Sagrada and 6-Mercaptopurine Together: Common Questions

Is it safe to take Cascara Sagrada with 6-Mercaptopurine?
We do not list a known interaction between Cascara Sagrada and 6-Mercaptopurine. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Cascara Sagrada and 6-Mercaptopurine have any of the same side effects?
Yes — our sources link each of them separately to 3 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
How was the Cascara Sagrada and 6-Mercaptopurine combination checked?
Interactions in our licensed database are recorded against drug classes. 6-Mercaptopurine is filed under 3 classifications, and Cascara Sagrada has documented interactions with 6 drug classes — none of 6-Mercaptopurine's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Cascara Sagrada interact with any other medications?
Yes. Cascara Sagrada has 745 documented drug interactions in our database — 6-Mercaptopurine is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does 6-Mercaptopurine interact with any supplements?
Yes. 6-Mercaptopurine has documented interactions with 106 supplements in our database — Cascara Sagrada is not one of them. The 6-Mercaptopurine interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Cascara Sagrada monograph Uses, safety profile, and every drug interaction in one place Mercaptopurine drug information The full plain-English guide to this medication 6-Mercaptopurine supplement interactions Every supplement checked against 6-Mercaptopurine, 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 References The 9 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About 6-Mercaptopurine 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.