Drug & supplement interaction

Hemlock + Tadalafil

Tadalafil brand names: Cialis, Tadliq.

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 Hemlock and Tadalafil 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

Hemlock and Tadalafil

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 Tadalafil and Hemlock 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Hemlock at all — not against Tadalafil, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Hemlock safety at a glance

Hemlock overall Avoid Hemlock is a deadly poison and should never be taken in any amount.
Pregnancy Unsafe When used orally because ingestion can be lethal; avoid using. Read the full pregnancy detail
Breastfeeding Unsafe When used orally because ingestion can be lethal; 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 Tadalafil and Hemlock? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Hemlock and Tadalafil May Share a Side Effect

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.

  • Muscle pain Additional detail

    Hemlock

    “Hemlock is generally regarded as unsafe for use. Any benefits of therapy may not outweigh the risk of toxicity. Orally, hemlock can cause burning of the mouth, throat, and abdomen, nausea, vomiting, excessive urination, salivation, drowsiness, mydriasis, muscle pain, rapid muscle swelling and stiffness, rhabdomyolysis, and tachycardia followed by bradycardia.”

    Hemlock · Natural Medicines adverse-effect record, reported in muscle breakdown.

    6 sources cited
    1. 6340. Drummer OH, Roberts AN, Bedford PJ, et al. Three deaths from hemlock poisoning. Med J Aust 1995;162:592-3. PubMed
    2. 6341. Frank BS, Panter KE. Ingestion of poison hemlock (Conium maculatum). West J Med 1995;163:573-4.
    3. 54709. Biberci, E., Altuntas, Y., Cobanoglu, A., and Alpinar, A. Acute respiratory arrest following hemlock (Conium maculatum) intoxication. J.Toxicol.Clin.Toxicol. 2002;40(4):517-518.
    4. 54711. Foster, P. F., McFadden, R., Trevino, R., Galliardt, S., Kopczewski, L. A., Gugliuzza, K., Gonzalez, Z., and Wright, F. Successful transplantation of donor organs from a hemlock poisoning victim. Transplantation 9-15-2003;76(5):874-876. PubMed
    5. 54712. Vetter, J. Poison hemlock (Conium maculatum L.). Food Chem.Toxicol. 2004;42(9):1373-1382. PubMed
    6. 54716. Rizzi, D., Basile, C., Di Maggio, A., Sebastio, A., Introna, F., Jr., Rizzi, R., Scatizzi, A., De Marco, S., and Smialek, J. E. Clinical spectrum of accidental hemlock poisoning: neurotoxic manifestations, rhabdomyolysis and acute tubular necrosis. Nephr PubMed

    “Orally, hemlock can cause muscle pain, rapid muscle swelling and stiffness, and rhabdomyolysis. Plasma exchange effectively improved the signs of rhabdomyolysis in one case of hemlock poisoning.”

    Hemlock · Natural Medicines adverse-effect record, reported in muscle breakdown.

    5 sources cited
    1. 6340. Drummer OH, Roberts AN, Bedford PJ, et al. Three deaths from hemlock poisoning. Med J Aust 1995;162:592-3. PubMed
    2. 6341. Frank BS, Panter KE. Ingestion of poison hemlock (Conium maculatum). West J Med 1995;163:573-4.
    3. 54712. Vetter, J. Poison hemlock (Conium maculatum L.). Food Chem.Toxicol. 2004;42(9):1373-1382. PubMed
    4. 110410. Boskabadi J, Askari Z, Zakariaei Z, Fakhar M, Tabaripour R. Mild-to-severe poisoning due to Conium maculatum as toxic herb: A case series. Clin Case Rep. 2021 Jul 23;9(7):e04509.
    5. 54727. Montemurro, N. E., Di Maggio, A., Strippoli, P., Coviello, F., Godino, F., Miloro, G., and Scatizzi, A. Combined dialysis and plasma-exchange in acute renal failure. Biomater.Artif.Cells Immobilization Biotechnol. 1993;21(2):283-287. PubMed

    Tadalafil

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

Reported for Hemlock but not commonly for Tadalafil: seizures, kidney problems, severe muscle breakdown and raised blood pressure.

Effects for Tadalafil come from the ADVERSE REACTIONS section of its FDA label; effects for Hemlock come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 98,103 voluntary FDA FAERS reports for Tadalafil 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

Hemlock in Pregnancy & Breastfeeding

Pregnancy And Lactation Unsafe

When used orally because ingestion can be lethal; 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

From our Q&A

Questions About Hemlock or Tadalafil

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

This page covers Hemlock only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tadalafil page lists 144 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 · 98 moderate · 41 minor.

From our pharmacist’s overview on the Tadalafil page

“Grapefruit juice is the first thing to know about if you take tadalafil (Cialis, Tadliq). It blocks CYP3A4, the enzyme that clears the drug, so blood levels climb and side effects like a steep drop in blood pressure become more likely.”

Reviewed by 2 · Jul 18, 2026

Open the Tadalafil interaction page

One more smart check

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

We hold 9 real supplement products containing Hemlock, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Hemlock. Even though Hemlock itself has no known interaction with Tadalafil, 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 Hemlock and Tadalafil 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 Hemlock
Steady interest

#1,086 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Tadalafil
Top 1%

#16 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 Hemlock reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Hemlock and Tadalafil records this page draws on were last updated July 10, 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 Hemlock

What is Hemlock?

  • Historical sedative or pain reliever
  • Traditional treatment for muscle spasms
  • Folk use for joint and nerve pain
  • Historical execution poison
  • Homeopathic preparations

Hemlock (Conium maculatum) is a highly poisonous plant that has no safe or proven medicinal use today. Even small amounts can cause paralysis and death, so it should never be consumed or applied to the body. Do not use hemlock or any product containing it.

Conium maculatum · Apiaceae · Whole plant, including leaves, seeds, stems, and roots (all parts are poisonous) · Not safely used in any form; historically prepared as extracts, tinctures, or poultices

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

Hemlock: dosing

There is no safe dose of hemlock. It is not a supplement and should never be measured out or taken. Even a small amount of plant material or seeds can be fatal to humans and animals.Do not buy, prepare, or consume any product that contains Conium maculatum.

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

Read the full Hemlock monograph & all interactions
Medication

About Tadalafil

What Is Tadalafil Used For?

Brand names: Cialis, Tadliq

Tadalafil tablets (including Cialis and generic tadalafil) are used to treat erectile dysfunction (ED), the symptoms of benign prostatic hyperplasia (BPH — an enlarged prostate), or both conditions together. When used with the drug finasteride to start BPH treatment, this combination is recommended for up to 26 weeks.

Adcirca, Alyq (tablets), and Tadliq (oral suspension) are indicated specifically for pulmonary arterial hypertension (PAH — high blood pressure in the lungs), to improve the ability to exercise.

Most-Reported Side Effects for Tadalafil

From FAERS, the FDA’s public side-effect reporting system (99,210 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Dyspnea 11,917 reports
Headache 10,982 reports
Diarrhea 8,020 reports
Nausea 6,697 reports
Fatigue 6,080 reports
See full Tadalafil drug information
Keep checking

Other Drugs & Hemlock

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Hemlock list.

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

Hemlock References

The 18 references that drive our Hemlock 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. Lopez TA, Cid MS, Bianchini ML. Biochemistry of hemlock (Conium maculatum L.) alkaloids and their acute and chronic toxicity in livestock. A review. Toxicon 1999;37:841-65. PubMed
  2. Drummer OH, Roberts AN, Bedford PJ, et al. Three deaths from hemlock poisoning. Med J Aust 1995;162:592-3. PubMed
  3. Frank BS, Panter KE. Ingestion of poison hemlock (Conium maculatum). West J Med 1995;163:573-4.
  4. Carod-Artal FJ. [Neurological syndromes linked with the intake of plants and fungi containing a toxic component (I). Neurotoxic syndromes caused by the ingestion of plants, seeds and fruits]. Rev Neurol 2003;36:860-71.
  5. Biberci, E., Altuntas, Y., Cobanoglu, A., and Alpinar, A. Acute respiratory arrest following hemlock (Conium maculatum) intoxication. J.Toxicol.Clin.Toxicol. 2002;40(4):517-518.
  6. Foster, P. F., McFadden, R., Trevino, R., Galliardt, S., Kopczewski, L. A., Gugliuzza, K., Gonzalez, Z., and Wright, F. Successful transplantation of donor organs from a hemlock poisoning victim. Transplantation 9-15-2003;76(5):874-876. PubMed
  7. Vetter, J. Poison hemlock (Conium maculatum L.). Food Chem.Toxicol. 2004;42(9):1373-1382. PubMed
  8. Rizzi, D., Basile, C., Di Maggio, A., Sebastio, A., Introna, F., Jr., Rizzi, R., Scatizzi, A., De Marco, S., and Smialek, J. E. Clinical spectrum of accidental hemlock poisoning: neurotoxic manifestations, rhabdomyolysis and acute tubular necrosis. Nephr PubMed
  9. Rizzi, D., Basile, C., Di Maggio, A., Sebastio, A., Introna, F., Jr., Rizzi, R., Bruno, S., Scatizzi, A., and De Marco, S. Rhabdomyolysis and acute tubular necrosis in coniine (hemlock) poisoning. Lancet 12-16-1989;2(8677):1461-1462. PubMed
  10. Rizzi, D., Introna, F., Jr., Gagliano, Candela R., Di Nunno, C., Ricco, R., Recchia, R., and De, Michele, V. [Toxic rhabdomyolysis and tubular necrosis in hemlock poisoning. 4 case reports]. Clin.Ter. 2-15-1988;124(3):193-201.
  11. Montemurro, N. E., Di Maggio, A., Strippoli, P., Coviello, F., Godino, F., Miloro, G., and Scatizzi, A. Combined dialysis and plasma-exchange in acute renal failure. Biomater.Artif.Cells Immobilization Biotechnol. 1993;21(2):283-287. PubMed
  12. Scatizzi, A., Di Maggio, A., Rizzi, D., Sebastio, A. M., and Basile, C. Acute renal failure due to tubular necrosis caused by wildfowl-mediated hemlock poisoning. Ren Fail. 1993;15(1):93-96. PubMed
  13. Brtalik D, Stopyra J, Hannum J. Intravenous poison hemlock injection resulting in prolonged respiratory failure and encephalopathy. J Med Toxicol. 2017;13(2):180-182. PubMed
  14. Konca C, Kahramaner Z, Bosnak M, Kocamaz H. Hemlock (Conium Maculatum) poisoning in a child. Turk J Emerg Med. 2016;14(1):34-6. DOI
  15. Chen HY, Horng H, Rowley F, Smollin C. Rapid respiratory arrest after ingestion of poison hemlock mistaken for wild celery. Clin Toxicol (Phila). 2017;55(2):155-156. 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 Hemlock and Tadalafil Together: Common Questions

Is it safe to take Hemlock with Tadalafil?
We do not list a known interaction between Hemlock and Tadalafil. 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 Hemlock and Tadalafil have any of the same side effects?
Yes — our sources link each of them separately to one 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.
Does Tadalafil interact with any supplements?
Yes. Tadalafil has documented interactions with 144 supplements in our database — Hemlock is not one of them. The Tadalafil 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

Hemlock monograph Uses, safety profile, and every drug interaction in one place Tadalafil drug information The full plain-English guide to this medication Tadalafil supplement interactions Every supplement checked against Tadalafil, 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 18 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Tadalafil and Hemlock?

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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.