Drug & supplement interaction

Colocynth + Nadolol

Nadolol brand names: Corgard, Nadolol.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Colocynth and Nadolol 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

Colocynth and Nadolol

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 Nadolol and Colocynth 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.

Colocynth safety at a glance

Colocynth overall Avoid Colocynth is a strong irritant and poison that can cause severe gut damage and death.
Pregnancy Avoid It may stimulate the uterus and is considered unsafe in pregnancy.
Breastfeeding Unsafe When used orally due to severe gastrointestinal toxicity; avoid using. 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 Nadolol and Colocynth? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Nadolol

Interactions in our licensed database are recorded against drug classes, not just single drug names. Nadolol is filed under 5 classifications — including beta-blockers, antihypertensive drugs, seizure threshold lowering drugs. Colocynth has documented interactions with 5 drug classes — the most serious being antidiabetes drugs (moderate), digoxin (lanoxin) (moderate) and diuretic drugs (moderate) — and none of Nadolol’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

Colocynth Does Interact With Other Medications

Colocynth has 185 moderate known drug interactions in our database — Nadolol isn’t one of them. If you take anything else, check it against the full list below.

Moderate 185 No known interaction 2,645 (incl. Nadolol)
Taking anything else?

Check Another of Your Medications Against Colocynth

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

What to actually watch for

No Interaction Found — But Data Suggests Colocynth and Nadolol 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.

  • Itching Additional detail

    Colocynth

    “Topically, mild pruritus has been reported in one patient that used a sesame oil-based colocynth fruit extract in a small clinical study.”

    Colocynth · Natural Medicines adverse-effect record, reported in pruritus.

    1 source cited
    1. 98602. Heydari M, Homayouni K, Hashempur MH, Shams M. Topical Citrullus colocynthis (bitter apple) extract oil in painful diabetic neuropathy: A double-blind randomized placebo-controlled clinical trial. J Diabetes. 2016;8(2):246-52. DOI

    Nadolol

    Listed in the ADVERSE REACTIONS section of the FDA label for Nadolol. Read the label on DailyMed ›

  • Diarrhea reported in 5.9% of FDA reports for Nadolol Additional detail

    Colocynth

    “Orally, ingestion of colocynth 0.6-1 grams can cause severe irritation of the gastric mucosa and bloody diarrhea (2,18). Cases of bloody diarrhea and intestinal cramps have been reported in case reports of individuals consuming the fresh fruit, the 'size of an orange' or unknown amounts of the extract. Colocynth ingestion can also cause acute toxic colitis.”

    Colocynth · Natural Medicines adverse-effect record, reported in diarrhea.

    5 sources cited
    1. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    3. 98601. Khan SA, Shelleh HH, Bhat AR, Bhat KS. Colocynth toxicity. A possible cause of bloody diarrhea. Saudi Med J. 2003;24(8):904-6. DOI
    4. 10653. Goldfain D, Lavergne A, Galian A, et al. Peculiar acute toxic colitis after ingestion of colocynth: a clinicopathological study of three cases. Gut 1989;30:1412-18.. PubMed
    5. 98604. Huseini HF, Darvishzadeh F, Heshmat R, Jafariazar Z, Raza M, Larijani B. The clinical investigation of Citrullus colocynthis (L.) schrad fruit in treatment of Type II diabetic patients: a randomized, double blind, placebo-controlled clinical trial. Phytot

    Nadolol

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

Reported for Colocynth but not commonly for Nadolol: kidney problems and seizures.

Effects for Nadolol come from the ADVERSE REACTIONS section of its FDA label; effects for Colocynth come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 7,530 voluntary FDA FAERS reports for Nadolol 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

Colocynth in Pregnancy & Breastfeeding

Lactation Unsafe

When used orally due to severe gastrointestinal toxicity; avoid using.

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

Everything else you take

See Every Supplement That Interacts With Nadolol

This page covers Colocynth only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Nadolol page lists 145 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), Green Tea (major) and Indian Snakeroot (major).

By severity: 6 major · 119 moderate · 20 minor.

From our pharmacist’s overview on the Nadolol page

“If you take nadolol (Corgard) for blood pressure, angina, or heart rhythm, treat this list with real care, and green tea is the surprise at the top. In a clinical study, green tea cut nadolol blood levels by roughly 85 percent, which can quietly leave you undertreated.”

Reviewed by 2 · Jul 18, 2026

Open the Nadolol interaction page

One more smart check

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

We hold 2 real supplement products containing Colocynth, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Colocynth. Even though Colocynth itself has no known interaction with Nadolol, 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 Colocynth and Nadolol 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 Colocynth
Steady interest

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

29 days ago today
Medication Nadolol
Top half

#1,166 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 Colocynth reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Colocynth and Nadolol 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 Colocynth

What is Colocynth?

  • Constipation
  • Digestive complaints
  • Diabetes (traditional use)
  • Joint and nerve pain
  • Skin conditions

Colocynth is a bitter desert gourd used in traditional medicine mainly as a powerful laxative, but it is highly toxic and can cause severe, sometimes deadly poisoning even at small doses. There is not enough good human evidence to support its use, and most pharmacists would advise against taking it. If you are curious about it, talk to a doctor or pharmacist before using any product that contains it.

Citrullus colocynthis · Cucurbitaceae · Fruit (pulp), seeds, and root · Dried fruit pulp, powder, capsules, traditional and homeopathic preparations

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

Colocynth: dosing

There is no established safe dose of colocynth for general use, and most health authorities and pharmacists do not recommend taking it at all because of its toxicity. Never take raw colocynth fruit, pulp, or seeds.

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

Read the full Colocynth monograph & all interactions
Medication

About Nadolol

What Is Nadolol Used For?

Brand names: Corgard, Nadolol

Nadolol tablets are used for two main conditions: high blood pressure (hypertension) and angina pectoris (ongoing chest pain caused by reduced blood flow to the heart). Lowering high blood pressure reduces the risk of stroke and heart attack.

For high blood pressure, nadolol may be prescribed on its own or combined with other blood pressure medications, especially thiazide-type diuretics (water pills). For angina, it is used for long-term management to help reduce how often chest pain occurs.

Most-Reported Side Effects for Nadolol

From FAERS, the FDA’s public side-effect reporting system (7,530 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Macular degeneration 831 reports
Nausea 673 reports
Headache 603 reports
Fatigue 526 reports
Weight decreased 464 reports
See full Nadolol drug information
Keep checking

Other Drugs & Colocynth

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

0Major
185Moderate
0Minor
2,644No known interaction
185 Moderate 2,644 No interaction
Moderate

185 interactions

Showing 60 of 185 moderate interactions — see all 185 on the Colocynth page.

No interaction 2,644 drugs checked — show the list

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

Showing the 60 most looked-up of 2,644 medications checked with no known interaction — see the full Colocynth list.

See the full Colocynth interactions page
See every supplement checked against Nadolol, ranked by severity
Evidence & sources

Colocynth References

The 9 references that drive our Colocynth 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. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  4. Osol and Farar. The Dispensatory of the United States of America. 25th ed. JB Lippincott Co., 1955.
  5. Goldfain D, Lavergne A, Galian A, et al. Peculiar acute toxic colitis after ingestion of colocynth: a clinicopathological study of three cases. Gut 1989;30:1412-18.. PubMed
  6. Li Y, Zheng M, Zhai X, et al. Effect of Gymnema Sylvester, Citrullus colocynthis and Artemisa absinthum on blood glucose and lipid profile in diabetic human. Acta Pol Pharm. 2015;72(5):981-5.
  7. Khan SA, Shelleh HH, Bhat AR, Bhat KS. Colocynth toxicity. A possible cause of bloody diarrhea. Saudi Med J. 2003;24(8):904-6. DOI
  8. Heydari M, Homayouni K, Hashempur MH, Shams M. Topical Citrullus colocynthis (bitter apple) extract oil in painful diabetic neuropathy: A double-blind randomized placebo-controlled clinical trial. J Diabetes. 2016;8(2):246-52. DOI
  9. Huseini HF, Darvishzadeh F, Heshmat R, Jafariazar Z, Raza M, Larijani B. The clinical investigation of Citrullus colocynthis (L.) schrad fruit in treatment of Type II diabetic patients: a randomized, double blind, placebo-controlled clinical trial. Phytot

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 Colocynth and Nadolol Together: Common Questions

Is it safe to take Colocynth with Nadolol?
We do not list a known interaction between Colocynth and Nadolol. 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 Colocynth and Nadolol have any of the same side effects?
Yes — our sources link each of them separately to 2 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 Colocynth and Nadolol combination checked?
Interactions in our licensed database are recorded against drug classes. Nadolol is filed under 5 classifications, and Colocynth has documented interactions with 5 drug classes — none of Nadolol'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 Colocynth interact with any other medications?
Yes. Colocynth has 185 documented drug interactions in our database — Nadolol 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 Nadolol interact with any supplements?
Yes. Nadolol has documented interactions with 145 supplements in our database — Colocynth is not one of them. The Nadolol 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

Colocynth monograph Uses, safety profile, and every drug interaction in one place Nadolol drug information The full plain-English guide to this medication Nadolol supplement interactions Every supplement checked against Nadolol, 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 Nadolol and Colocynth?

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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.