Drug & supplement interaction

Water Hemlock + Risperidone

Risperidone brand names: Risperdal, Perseris.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Oct 4, 2026
The bottom line No known interaction

We found no known interaction between Water Hemlock and Risperidone 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

Water Hemlock and Risperidone

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 Risperidone and Water 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.

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.

Water Hemlock safety at a glance

Water Hemlock overall Avoid Water hemlock is deadly poisonous and should never be consumed.
Pregnancy Unsafe When used orally or topically. Water hemlock is toxic; avoid using. Read the full pregnancy detail
Breastfeeding Unsafe When used orally or topically. Water hemlock is toxic; 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 Risperidone and Water Hemlock? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Risperidone

Interactions in our licensed database are recorded against drug classes, not just single drug names. Risperidone is filed under 10 classifications — including antipsychotic drugs, qt interval-prolonging drugs, serotonergic drugs. Water Hemlock has documented interactions with 1 drug class — the most serious being lithium (moderate) — and none of Risperidone’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

Water Hemlock Does Interact With Other Medications

Water Hemlock has 1 moderate known drug interaction in our database — Risperidone isn’t one of them. If you take anything else, check it against the full list below.

Moderate 1 No known interaction 2,829 (incl. Risperidone)
Taking anything else?

Check Another of Your Medications Against Water Hemlock

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

What to actually watch for

No Interaction Found — But Data Suggests Water Hemlock and Risperidone 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. One of them is worth acting on rather than waiting out — marked below.

  • Seizures Worth acting on Additional detail

    Water Hemlock

    “Water hemlock is a known highly toxic plant and causes a variety of symptoms including vomiting, acute renal failure, marked metabolic acidosis, seizures and convulsions, or unconsciousness that may lead to death.”

    Water Hemlock · Natural Medicines adverse-effect record, reported in epilepsy.

    6 sources cited
    1. 6350. Applefeld JJ, Caplan ES. A case of water hemlock poisoning. JACEP 1979;8:401-3. PubMed
    2. 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
    3. 6351. Carlton BE, Tufts E, Girard DE. Water hemlock poisoning complicated by rhabdomyolysis and renal failure. Clin Toxicol 1979;14:87-92. PubMed
    4. 6348. Knutsen OH, Paszkowski P. New aspects in the treatment of water hemlock poisoning. J Toxicol Clin Toxicol 1984;22:157-66. PubMed
    5. 6346. Starreveld E, Hope E. Cicutoxin poisoning (water hemlock). Neurol 1975;25:730-4. PubMed
    6. 85535. Landers, D., Seppi, K., and Blauer, W. Seizures and death on a white river float trip. Report of water hemlock poisoning. West J.Med. 1985;142(5):637-640. DOI

    “According to case reports, oral ingestion may cause an explosive illness with seizures and convulsions, neurologic lethargy, or unconsciousness that may lead to death.”

    Water Hemlock · Natural Medicines adverse-effect record, reported in epilepsy.

    6 sources cited
    1. 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
    2. 85535. Landers, D., Seppi, K., and Blauer, W. Seizures and death on a white river float trip. Report of water hemlock poisoning. West J.Med. 1985;142(5):637-640. DOI
    3. 6348. Knutsen OH, Paszkowski P. New aspects in the treatment of water hemlock poisoning. J Toxicol Clin Toxicol 1984;22:157-66. PubMed
    4. 6346. Starreveld E, Hope E. Cicutoxin poisoning (water hemlock). Neurol 1975;25:730-4. PubMed
    5. 6350. Applefeld JJ, Caplan ES. A case of water hemlock poisoning. JACEP 1979;8:401-3. PubMed
    6. 85531. Heath, K. B. A fatal case of apparent water hemlock poisoning. Vet.Hum.Toxicol. 2001;43(1):35-36.

    Risperidone

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

  • A fast or pounding heartbeat / Low blood pressure Additional detail

    Water Hemlock

    “According to case reports, oral ingestion may cause an explosive illness with orthostatic hypotension or tachycardia.”

    Water Hemlock · Natural Medicines adverse-effect record, reported in hypotension.

    1 source cited
    1. 6350. Applefeld JJ, Caplan ES. A case of water hemlock poisoning. JACEP 1979;8:401-3. PubMed

    Risperidone

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

  • Stomach pain / Nausea Additional detail

    Water Hemlock

    “According to case reports, oral ingestion causes an explosive illness with nausea, vomiting, or abdominal cramps.”

    Water Hemlock · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    1 source cited
    1. 6350. Applefeld JJ, Caplan ES. A case of water hemlock poisoning. JACEP 1979;8:401-3. PubMed

    Risperidone

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

  • Tiredness Additional detail

    Water Hemlock

    Recorded for Water Hemlock in the same Natural Medicines adverse-effect record shown under Seizures above.

    Risperidone

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

  • Vomiting Additional detail

    Water Hemlock

    Recorded for Water Hemlock in the same Natural Medicines adverse-effect record shown under Seizures above.

    Risperidone

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

Reported for Water Hemlock but not commonly for Risperidone: severe muscle breakdown and kidney problems.

Effects for Risperidone come from the ADVERSE REACTIONS section of its FDA label; effects for Water Hemlock come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Water Hemlock in Pregnancy & Breastfeeding

Pregnancy And Lactation Unsafe

When used orally or topically. Water hemlock is toxic; 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 Water Hemlock or Risperidone

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

This page covers Water Hemlock only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Risperidone page lists 199 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 11 major · 147 moderate · 41 minor.

From our pharmacist’s overview on the Risperidone page

“Someone taking risperidone (Risperdal, Perseris) for schizophrenia or bipolar disorder depends on a steady blood level to stay well, and this list calls for genuine care, starting with its eleven major-rated entries. Most of the 199 ingredients can shift that level, because risperidone is cleared by liver enzymes that a long roster of…”

Reviewed by 2 · Jul 18, 2026

Open the Risperidone interaction page

How much people look this up

Where Water Hemlock and Risperidone 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 Water Hemlock
Steady interest

#1,187 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Risperidone
Steady interest

#2,073 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 Water Hemlock reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified October 4, 2026. The Water Hemlock and Risperidone 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 Water Hemlock

What is Water Hemlock?

  • Historically misused in folk practice (not recommended)
  • Sometimes confused with edible wild carrots or parsnips
  • No safe medicinal use

Water hemlock is one of the most poisonous plants in North America and is NOT a safe dietary supplement or herbal remedy. Even small amounts can cause violent seizures and death. Never eat, brew, or take any part of this plant, and seek emergency care immediately if exposure is suspected.

Cicuta maculata · Apiaceae · None — this is a toxic plant, not a usable supplement (roots are the most poisonous part) · Not used as a supplement; sometimes mistaken for edible wild plants

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

Water Hemlock: dosing

There is no safe dose of water hemlock. The only appropriate action with this plant is avoidance and, in case of exposure, emergency care.

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

Read the full Water Hemlock monograph & all interactions
Medication

About Risperidone

What Is Risperidone Used For?

Brand names: Risperdal, Perseris

Risperidone treats schizophrenia and bipolar I disorder. Oral risperidone (tablets, orally disintegrating tablets and oral solution) treats acute manic or mixed episodes of bipolar I disorder, alone or added to lithium or valproate.

Oral risperidone is also used for irritability linked to autistic disorder in children and adolescents. Long-acting injections (Uzedy, Perseris, Risperdal Consta, Rykindo and generic extended-release injectables) are used for schizophrenia. Uzedy, Risperdal Consta, Rykindo and the generic injectables are also used for maintenance treatment of bipolar I disorder. Perseris is labeled for schizophrenia in adults only.

See full Risperidone drug information
Keep checking

Other Drugs & Water Hemlock

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

0Major
1Moderate
0Minor
2,828No known interaction
1 Moderate 2,828 No interaction
Moderate

1 interaction

No interaction 2,828 drugs checked — show the list

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

Showing the 60 most looked-up of 2,828 medications checked with no known interaction — see the full Water Hemlock list.

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

Water Hemlock References

The 8 references that drive our Water 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. Starreveld E, Hope E. Cicutoxin poisoning (water hemlock). Neurol 1975;25:730-4. PubMed
  2. Knutsen OH, Paszkowski P. New aspects in the treatment of water hemlock poisoning. J Toxicol Clin Toxicol 1984;22:157-66. PubMed
  3. Anon. Water hemlock poisoning - Maine, 1992. MMWR Morb Mortal Wkly Rep 1994;43:229-31. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/00026056.htm.
  4. Applefeld JJ, Caplan ES. A case of water hemlock poisoning. JACEP 1979;8:401-3. PubMed
  5. Carlton BE, Tufts E, Girard DE. Water hemlock poisoning complicated by rhabdomyolysis and renal failure. Clin Toxicol 1979;14:87-92. PubMed
  6. 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
  7. Heath, K. B. A fatal case of apparent water hemlock poisoning. Vet.Hum.Toxicol. 2001;43(1):35-36.
  8. Landers, D., Seppi, K., and Blauer, W. Seizures and death on a white river float trip. Report of water hemlock poisoning. West J.Med. 1985;142(5):637-640. DOI

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 Water Hemlock and Risperidone Together: Common Questions

Is it safe to take Water Hemlock with Risperidone?
We do not list a known interaction between Water Hemlock and Risperidone. 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 Water Hemlock and Risperidone have any of the same side effects?
Yes — our sources link each of them separately to 7 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 Water Hemlock and Risperidone combination checked?
Interactions in our licensed database are recorded against drug classes. Risperidone is filed under 10 classifications, and Water Hemlock has documented interactions with 1 drug class — none of Risperidone'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 Water Hemlock interact with any other medications?
Yes. Water Hemlock has 1 documented drug interaction in our database — Risperidone 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 Risperidone interact with any supplements?
Yes. Risperidone has documented interactions with 199 supplements in our database — Water Hemlock is not one of them. The Risperidone 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

Water Hemlock monograph Uses, safety profile, and every drug interaction in one place Risperidone drug information The full plain-English guide to this medication Risperidone supplement interactions Every supplement checked against Risperidone, 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 8 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Risperidone and Water 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.