Herb & supplement monograph

Canadian Hemp Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by ·Updated July 2026
What is this page for?

First and foremost: how Canadian Hemp interacts with medications. The heart of this page is the interaction list — every drug Canadian Hemp is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Canadian Hemp is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Canadian Hemp Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Canadian Hemp drug interaction appears low for most people, but it deserves real caution in anyone taking certain heart or fluid medications. Every listed interaction is rated moderate rather than major, and all rest on theoretical concerns rather than documented human reports.

Interactions deserving the most attention

The concern that stands out most involves digoxin and potassium-depleting diuretics such as furosemide and hydrochlorothiazide. Canadian Hemp naturally contains cardiac glycosides, compounds that act on the heart much like digoxin does, so combining them could in theory add to digoxin's effects and side effects. Diuretics that lower potassium could raise the risk of glycoside toxicity, since low potassium makes the heart more sensitive to these compounds. Digoxin is a narrow-margin medicine, so even a theoretical additive effect matters here.

What the rest of the list means

Although the list of interacting medications is fairly long, nearly all of it traces back to these two related concerns about the plant's cardiac glycosides. The interactions are predicted from what these compounds do in the body, not from studies showing harm in people, so most combinations have never been confirmed to cause problems.

Check your medications against Canadian Hemp

Based on HelloPharmacist’s Canadian Hemp interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Canadian Hemp

76 medications have a known interaction with Canadian Hemp, graded by severity. Select any drug for the full evidence-based detail.

2,830 drugs
Acetaminophen, Caffeine, PyrilamineMidol Max Strength Menstrual› Acetaminophen, Pamabrom, PyrilamineMidol Max Strength PMS, Pamprin, Pamprin ES› AcetazolamideAk-Zol, Diamox› Amiloride, HydrochlorothiazideAmil-Co, Amilzide, Moduret 25, Moduretic› Ammonium ChlorideAmmonium Chloride› Atenolol, ChlortalidoneAtenixCo, Tenoret 50, Totaretic› Atenolol, ChlorthalidoneTenoretic› Azilsartan, ChlorthalidoneEdarbyclor› Benazepril, HydrochlorothiazideLotensin HCT› BendroflumethiazideAprinox, Naturetin, Neo-NaClex› Bendroflumethiazide, NadololCorzide› Bendroflumethiazide, PotassiumCentyl K, Neo-NaClex-K› Bendroflumethiazide, Rauwolfia SerpentinaRauzide› BenzthiazideExna› Bisoprolol, HydrochlorothiazideZiac› BumetanideBurinex› Bumetanide, PotassiumBurinex K› Caffeine, Potassium Salicylate, SalicylamideTrim-Elim› Candesartan Cilexetil, HydrochlorothiazideAtacand HCT› Captopril, HydrochlorothiazideAcezide, Capozide› ChlorothiazideDiuril› Chlorothiazide, MethyldopaAldochlor, Aldoclor 150, Aldoclor 250› Chlorothiazide, ReserpineDiupres› ChlorthalidoneHygroton, Thalitone› Chlorthalidone, ClonidineClorpres, Combipres› Cryptenamine, MethyclothiazideDiutensen› CyclothiazideAnhydron, Fluidil› Deserpidine, HydrochlorothiazideOreticyl, Oreticyl Forte› Deserpidine, MethyclothiazideEnduronyl, Enduronyl Forte› DigoxinDigitek, Lanoxicaps, Lanoxin›
Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

  • Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
  • Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
  • Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
  • No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

  • Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
  • Probable. 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.
  • Possible. 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
  • Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

  • Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
  • Each drug listed above links to the full report for that exact Canadian Hemp combination — clinical detail, likelihood, evidence level, and citations.
  • Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.
The big picture

The kinds of drugs Canadian Hemp affects

Every type of medication (drug category) Canadian Hemp is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 2 drug categories Canadian Hemp interacts with
Digoxin (lanoxin)Diuretic Drugs
Digoxin (Lanoxin)

Canadian hemp contains cardiac glycosides. Theoretically, concomitant use of Canadian hemp with digoxin (Lanoxin) might increase therapeutic effects and adverse effects.

Likelihood Possible Evidence D
Diuretic Drugs

Canadian hemp contains cardiac glycosides. Theoretically, concomitant use of potassium depleting diuretics and Canadian hemp can increase the risk of cardiac glycoside toxicity due to potassium depletion. Some diuretics that can deplete potassium include chlorothiazide (Diuril), chlorthalidone (Thalitone), furosemide (Lasix), hydrochlorothiazide (HCTZ, Hydrodiuril, Microzide), and others.

Likelihood Possible Evidence D
Monograph

Canadian Hemp: Uses, Safety & Side Effects

Medically reviewed by · Reviewed July 2026 ·
The bottom line

Canadian Hemp (Apocynum cannabinum) is a toxic North American plant historically used as a heart stimulant and diuretic, but it contains potent cardiac glycosides that can cause dangerous heart and poisoning effects. It is not a safe or recommended dietary supplement, and there is no reliable modern evidence supporting its use. Avoid using it and talk to a pharmacist or doctor about safer, proven options.

Scientific name
Apocynum cannabinum
Family
Apocynaceae
Part used
Dried roots and rhizomes
Common forms
Tincture, dried root, traditional decoction (rarely sold as a modern supplement)
People commonly use it for
  • Heart-related swelling (dropsy/edema)
  • Fluid retention
  • Constipation
  • Urinary problems
  • Traditional folk remedy uses

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance
OverallBest avoided

It contains toxic cardiac glycosides and is considered a poisonous plant, not a safe supplement.

PregnancyLikely Unsafe

When used orally due to the toxic potential of its cardiac glycoside constituents; avoid using.

Read the full pregnancy detail
BreastfeedingLikely Unsafe

When used orally due to the toxic potential of its cardiac glycoside constituents; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Canadian Hemp (Apocynum cannabinum) is a tall, leafy perennial plant native to North America. It is also sometimes called dogbane or Indian hemp, but it is not related to true hemp or cannabis. The name "hemp" comes from the plant's tough, fibrous stems, which Native peoples once used to make cord and rope.

Historically, the root was used in traditional and early folk medicine as a strong heart stimulant and as a remedy to remove excess body fluid. It grows in fields, along roadsides, and near streams. Today it is rarely sold as a supplement, and it is widely recognized as a toxic plant rather than a safe herbal product.

How it works

Canadian Hemp contains cardiac glycosides (such as cymarin and related compounds). These are powerful substances that affect the way the heart muscle contracts, similar to the action of digitalis-type drugs. This is why it was once used to strengthen a weak heartbeat and to help the body release fluid.

The problem is that the amount of these compounds in the plant is not standardized, and the line between an active dose and a poisonous dose is very narrow. Most of what is known comes from older reports and laboratory understanding of cardiac glycosides, not from controlled human studies.

Effectiveness

Does Canadian Hemp work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by .

Evidence overview · 4 uses evaluated
4 Insufficient evidence
How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.
2Likely EffectiveGood evidence, though not yet conclusive.
3Possibly EffectiveSome evidence suggests a benefit.
4Possibly IneffectiveSome evidence it may not help.
5Likely IneffectiveFairly strong evidence it doesn’t help.
6IneffectiveStrong evidence it doesn’t work.
7Insufficient Reliable Evidence to RateToo little research to say either way.

For Canadian Hemp, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 4 conditions — evidence insufficient to rate
Insufficient Reliable Evidence To Rate Androgenic alopecia
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using topical Canadian hemp for androgenic alopecia, there is insufficient reliable information about the clinical effects of Canadian hemp for this condition.

Insufficient Reliable Evidence To Rate Cough
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using oral Canadian hemp for cough, there is insufficient reliable information about the clinical effects of Canadian hemp for this condition.

Insufficient Reliable Evidence To Rate Heart failure
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using oral Canadian hemp for heart failure, there is insufficient reliable information about the clinical effects of Canadian hemp for this condition.

Insufficient Reliable Evidence To Rate Warts
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using topical Canadian hemp for warts, there is insufficient reliable information about the clinical effects of Canadian hemp for this condition.

Source & disclaimer. Effectiveness ratings and evidence summaries are provided by Natural Medicines (Therapeutic Research Center) and shown as licensed. Where Natural Medicines hasn’t rated a use, HelloPharmacist’s pharmacists may add their own reviewed rating and evidence (each such entry is labeled). This is educational information, not medical advice — talk with your pharmacist or doctor before starting, stopping, or changing a supplement.

Safety & precautions

Canadian Hemp is considered a poisonous plant. Its sap, leaves, and roots can be harmful, and swallowing the plant can cause serious poisoning. Because of the cardiac glycosides, it can affect heart rhythm in dangerous ways.

People with heart disease, kidney problems, or who take any heart medicine are at especially high risk. Pregnant and breastfeeding women should not use it at all because of its toxicity and the possibility of harming the uterus or the baby. Children and older adults should also avoid it.

Because this plant can be dangerous, the safest choice is to avoid using it. If you are looking for help with swelling, heart issues, or fluid retention, talk to a pharmacist or doctor about proven, safer treatments.

Side effects

Reported effects from Canadian Hemp and similar cardiac-glycoside plants include nausea, vomiting, diarrhea, stomach pain, dizziness, and a slow or irregular heartbeat. Skin contact with the sap may cause irritation.

Serious poisoning can lead to dangerous heart rhythm changes, confusion, and even death. If someone swallows this plant or shows signs of poisoning, seek emergency medical care or contact a poison control center right away.

Canadian Hemp: Reported Adverse Effects

Documented safety reports on Canadian Hemp from the evidence-graded Natural Medicines (TRC Healthcare) database, shown word-for-word from the licensed record.

Orally, Canadian hemp can cause digitalis-like toxicity due to its cardiac glycoside constituents. Symptoms of toxicity can include bradycardia with hypotension, increased heart contractions, and reflex hypertension. Canadian hemp can also cause topical irritation of the gastrointestinal mucous membranes. This irritation can result in a higher incidence of nausea and vomiting than with other cardiac glycoside-containing plants (such as digitalis).

  1. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
Reports by condition
Hypertension Cardiovascular

Orally, Canadian hemp might cause bradycardia with low blood pressure, increased heart contractions, and reflex hypertension.

  1. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
Nausea and vomiting Gastrointestinal

Orally, Canadian hemp can cause topical irritation of the gastrointestinal mucous membranes. This irritation can result in a higher incidence of nausea and vomiting than with other cardiac glycoside-containing plants (such as digitalis).

  1. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
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.

Adverse-effects data: Natural Medicines, Therapeutic Research Center

Dosing

There is no established safe dose for Canadian Hemp, and we do not provide one. Because it contains potent and potentially deadly heart-acting compounds with a very narrow safety margin, no general dosing guidance can be given.

If you come across a product containing Apocynum cannabinum, do not take it without speaking to a pharmacist or doctor first. In nearly all cases, safer and better-studied options are available.

Pregnancy & Breastfeeding

Canadian Hemp & Pregnancy

Likely Unsafe

When used orally due to the toxic potential of its cardiac glycoside constituents; avoid using.

  1. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

Canadian Hemp & Breastfeeding

Likely Unsafe

When used orally due to the toxic potential of its cardiac glycoside constituents; avoid using.

  1. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
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

Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center

References & further reading

The 2 references that drive our Canadian Hemp 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. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
Keep reading

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.

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

Pharmacist Counseling Corner

Canadian Hemp: Common Questions

What is Canadian Hemp used for, and does it work?
People use Canadian Hemp for a range of reasons, but according to the Natural Medicines database the current clinical evidence is insufficient to confirm it works for the specific conditions it has been studied for. See the graded list on this page, and talk to your pharmacist or doctor before relying on it for any condition.
Does Canadian Hemp interact with prescription medications?
Yes. We list 76 medications with a known interaction with Canadian Hemp. Use the checker above to see how Canadian Hemp interacts with a specific drug.
How are Canadian Hemp interactions rated?
Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.
Is it safe to take Canadian Hemp with my medications?
It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.
Where does this Canadian Hemp interaction information come from?
Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.
Is Canadian Hemp the same as cannabis or CBD?
No. Despite the name, Canadian Hemp (Apocynum cannabinum) is not related to cannabis or true hemp. It got the name from its fibrous stems, which were used to make rope, not because of any link to marijuana or CBD.
Is Canadian Hemp safe to take as a supplement?
No. It contains toxic cardiac glycosides that can cause serious heart and poisoning effects, and there is no reliable evidence it is safe or effective. It is best avoided.
What did people traditionally use Canadian Hemp for?
It was historically used as a heart stimulant and to remove excess body fluid (for swelling or dropsy), as well as a laxative. These uses have been replaced by safer modern medicines.
What should I do if someone swallows this plant?
Treat it as a possible poisoning. Seek emergency medical care or call your local poison control center right away, especially if there is vomiting, dizziness, or an irregular heartbeat.

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

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