Hemlock Water Dropwort + Atezolizumab
Atezolizumab brand name: Tecentriq.
We found no known interaction between Hemlock Water Dropwort and Atezolizumab 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.
Hemlock Water Dropwort and Atezolizumab
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 Atezolizumab and Hemlock Water Dropwort 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 Water Dropwort at all — not against Atezolizumab, 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 Water Dropwort safety at a glance
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.
Hemlock Water Dropwort in Pregnancy & Breastfeeding
When used orally. Ingestion can be lethal.
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
See Every Supplement That Interacts With Atezolizumab
This page covers Hemlock Water Dropwort only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Atezolizumab page lists 54 supplements it has a documented interaction with, worst first, each one explained.
The most serious there right now: Active Hexose Correlated Compound (ahcc) (moderate), Alfalfa (moderate), American Ginseng (moderate), Andrographis (moderate) and Ashwagandha (moderate).
By severity: 52 moderate · 2 minor.
From our pharmacist’s overview on the Atezolizumab page
“Atezolizumab (Tecentriq) is cancer immunotherapy, a drug designed to release the brakes on your own immune system so it can attack tumors. That mechanism explains why nearly every one of the 54 supplements and herbs on this page made the list: 53 are flagged because they appear to stimulate immune activity, based mostly on lab and anim…”
Reviewed by 2 · Jul 18, 2026
Taking Hemlock Water Dropwort as Part of a Dietary Supplement Product? Check It for Interactions
We hold 1 real supplement products containing Hemlock Water Dropwort, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Hemlock Water Dropwort. Even though Hemlock Water Dropwort itself has no known interaction with Atezolizumab, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:
Where Hemlock Water Dropwort and Atezolizumab 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.
#976 of 1,452 supplements looked up here in the last 7 days
#2,105 of 2,830 medications looked up here in the last 7 days
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 Water Dropwort reference on this page ↓
- Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Hemlock Water Dropwort and Atezolizumab 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.
About Hemlock Water Dropwort
What is Hemlock Water Dropwort?
- Historical/folk wound poultices (unsafe)
- Traditional topical use (unsafe)
- Subject of toxicology research
Hemlock water dropwort is one of the most poisonous plants in Europe and is NOT a safe dietary supplement or herbal remedy. Every part of the plant is toxic, and even small amounts can cause seizures, heart problems, and death. Do not consume it in any form.
Oenanthe crocata · Apiaceae · Whole plant, especially the roots (highly toxic) · Not used as a supplement; the plant is a poisonous wild herb
An interaction check asks whether these two react with each other — it does not ask whether Hemlock Water Dropwort is a good idea for someone in your situation. Here is what our Hemlock Water Dropwort record says about it on its own.
Hemlock Water Dropwort: dosing
There is no safe dose of hemlock water dropwort. The only correct "dose" is none at all.
From our Hemlock Water Dropwort monograph — the full record covers uses, side effects and every documented interaction.
About Atezolizumab Injection
What Is Atezolizumab Injection Used For?
Brand name: Tecentriq
Tecentriq (atezolizumab) is used to treat a range of cancers in adults. It can be used alone or combined with other cancer medicines depending on the cancer type and stage. Approved uses include non-small cell lung cancer (NSCLC) — both after surgery and in metastatic (spread) disease — extensive-stage small cell lung cancer (ES-SCLC), unresectable or metastatic hepatocellular carcinoma (liver cancer), BRAF V600 mutation-positive melanoma, and muscle invasive bladder cancer after surgery.
Tecentriq is also approved — as a single agent — for adult and pediatric patients aged 2 and older with unresectable or metastatic alveolar soft part sarcoma (ASPS), a rare soft tissue cancer. Several of these uses require tumor testing (such as PD-L1 expression or specific gene mutations) before Tecentriq is selected as treatment.
Other Drugs & Hemlock Water Dropwort
Browse every other medication we’ve checked against Hemlock Water Dropwort — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
No interaction 2,829 drugs checked — show the list
We also checked Hemlock Water Dropwort against these medications and found no known interaction in our sources. Open any page to confirm.
- Apixaban ›
- Levothyroxine ›
- Amlodipine ›
- Methylphenidate ›
- Warfarin ›
- Sertraline ›
- Testosterone ›
- Losartan Potassium ›
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- Hydroxyurea ›
- Abemaciclib ›
- Methamphetamine ›
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- Semaglutide ›
- Tirzepatide ›
- Warfarin Sodium ›
- Prednisone ›
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- Acyclovir ›
- Bupropion ›
- Metformin ›
- Amoxicillin ›
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- Amitriptyline ›
- Doxycycline ›
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- Fluoxetine ›
- Methotrexate ›
- Acetaminophen, Codeine ›
- Gabapentin ›
- Amphetamine ›
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- Isotretinoin ›
- Dextroamphetamine ›
- Azithromycin ›
- Clonazepam ›
- Quetiapine ›
- Omeprazole ›
- Amlodipine Besylate ›
- Methylene Blue ›
- Duloxetine ›
- Buspirone ›
- Letrozole ›
- Citalopram ›
- Ciprofloxacin ›
- Naproxen ›
Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Hemlock Water Dropwort list.
Hemlock Water Dropwort References
The 4 references that drive our Hemlock Water Dropwort 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.
- Fitzgerald P, Moss N, O'Mahony S, Whelton MJ. Accidental hemlock poisoning. Br Med J (Clin Res Ed) 1987;295:1657. PubMed
- Mitchell MI, Routledge PA. Hemlock water dropwort poisoning-a review. Clin Toxicol 1978;12:417-26. PubMed
- Ball MJ, Flather ML, Forfar JC. Hemlock water dropwort poisoning. Postgrad Med J 1987;63:363-5. PubMed
- Henry FJ, Cadiet J, Javaudin F, Rozec B. Oenantha Crocata: A Case Report of Multiple Poisoning with Fatal Outcome. J Emerg Med. 2020;59(1):e9-e11. 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.
Taking Hemlock Water Dropwort and Atezolizumab Together: Common Questions
Is it safe to take Hemlock Water Dropwort with Atezolizumab?
Do Hemlock Water Dropwort and Atezolizumab have any of the same side effects?
Does Atezolizumab interact with any supplements?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
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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.