Drug & supplement interaction

Wild Lettuce + Granisetron

Granisetron brand names: Kytril, Sustol.

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 Wild Lettuce and Granisetron 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 label for Granisetron states a food rule worth keeping to, and 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

Wild Lettuce and Granisetron

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 Granisetron and Wild Lettuce 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.

Wild Lettuce safety at a glance

Wild Lettuce overall Use caution Limited human safety data exist, and high doses have been linked to side effects.
Pregnancy Avoid Not enough safety information is available, so it is best avoided during pregnancy.
Breastfeeding Avoid There is no reliable safety data, so avoid use while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Pharmacist analysis

Studies are few and far between, but the only reported interactions with wild lettuce are with sedative drugs as wild lettuce is purported to have sedative effects.

This would include drugs like antihistamines, opioids, and benzodiazepines. These are detailed on our individual drug interaction pages.

Additionally, as wild lettuce may contain hyoscyamine, an anticholinergic drug, it should be used cautiously with other anticholinergic drugs due to the increased risk of side effects.


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Still wondering about combining Granisetron and Wild Lettuce? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Granisetron

Interactions in our licensed database are recorded against drug classes, not just single drug names. Granisetron is filed under 3 classifications — serotonergic drugs, serotonergic drugs, oral drugs. Wild Lettuce has documented interactions with 2 drug classes — the most serious being anticholinergic drugs (moderate) and cns depressants (moderate) — and none of Granisetron’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

Wild Lettuce Does Interact With Other Medications

Wild Lettuce has 393 moderate known drug interactions in our database — Granisetron isn’t one of them. If you take anything else, check it against the full list below.

Moderate 393 No known interaction 2,437 (incl. Granisetron)
Taking anything else?

Check Another of Your Medications Against Wild Lettuce

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

What to actually watch for

No Interaction Found — But Data Suggests Wild Lettuce and Granisetron 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.

  • An allergic reaction Worth acting on Additional detail

    Wild Lettuce

    “Topically, wild lettuce can cause contact dermatitis (4). It can cause an allergic reaction in individuals sensitive to the Asteraceae/Compositae family. Members of this family include ragweed, chrysanthemums, marigolds, daisies, and many other herbs.”

    Wild Lettuce · Natural Medicines adverse-effect record, reported in dermatitis.

    1 source cited
    1. 4. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.

    Granisetron

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

  • A fast or pounding heartbeat / Fever Additional detail

    Wild Lettuce

    “There is currently a limited amount of information on the adverse effects of wild lettuce. Orally, large amounts of wild lettuce, as well as eating prematurely harvested wild lettuce, can cause sweating, increased respiration, tachycardia, pupil dilation, dizziness, ringing in the ears, vision disorders, pressure in the head, somnolence, excitatory states (18, 93563), respiratory depression, coma, and death (4).

    Topi…”

    Wild Lettuce · Natural Medicines adverse-effect record, reported in cluster headache.

    2 sources cited
    1. 4. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
    2. 93566. Mullins ME, Horowitz BZ. The case of the salad shooters: intravenous injection of wild lettuce extract. Vet Hum Toxicol. 1998;40(5):290-1.

    “Intravenously, boiled wild lettuce, prepared by hand in combination with valerian root, has been reported to cause fever, severe headache, and tachycardia in three intravenous drug users. This reaction was hypothesized to be due to an immunologic response.”

    Wild Lettuce · Natural Medicines adverse-effect record, reported in cluster headache.

    1 source cited
    1. 93566. Mullins ME, Horowitz BZ. The case of the salad shooters: intravenous injection of wild lettuce extract. Vet Hum Toxicol. 1998;40(5):290-1.

    Granisetron

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

  • Drowsiness / Headache Additional detail

    Wild Lettuce

    “Orally, large amounts of wild lettuce or prematurely harvested wild lettuce has been reported to cause dizziness, pressure in the head, somnolence, anxiety, headache, excitatory states (18, 93563), and coma (4).”

    Wild Lettuce · Natural Medicines adverse-effect record, reported in anxiety.

    1 source cited
    1. 4. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.

    Granisetron

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

  • Anxiety or restlessness Additional detail

    Wild Lettuce

    Recorded for Wild Lettuce in the same Natural Medicines adverse-effect record shown under Drowsiness / Headache above.

    Granisetron

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

  • Stomach pain / Nausea Additional detail

    Wild Lettuce

    “Orally, wild lettuce has been reported to cause nausea, vomiting, and abdominal cramps.

    Intravenously, boiled wild lettuce, prepared by hand in combination with valerian root, has been reported to cause nausea and abdominal pain in three intravenous drug users.”

    Wild Lettuce · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    2 sources cited
    1. 93563. Besharat S, Besharat M, Jabbari A. Wild lettuce (Lactuca virosa) toxicity. BMJ Case Rep. 2009;2009. pii: bcr06.2008.0134.
    2. 93566. Mullins ME, Horowitz BZ. The case of the salad shooters: intravenous injection of wild lettuce extract. Vet Hum Toxicol. 1998;40(5):290-1.

    Granisetron

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

  • Vomiting Additional detail

    Wild Lettuce

    Recorded for Wild Lettuce in the same Natural Medicines adverse-effect record shown under Stomach pain / Nausea above.

    Granisetron

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

Reported for Wild Lettuce but not commonly for Granisetron: ringing in the ears, trouble passing urine, a skin rash and dizziness.

Effects for Granisetron come from the ADVERSE REACTIONS section of its FDA label; effects for Wild Lettuce 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.

How to take them

Some Granisetron Products Have a Food Rule — Wild Lettuce Should Not Break It

At least one FDA label for a product containing Granisetron says to take it on an empty stomach. Most supplements — Wild Lettuce included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Granisetron on its own and move Wild Lettuce to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Granisetron products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

Recommended Dosage ( 2.2 ): The recommended dosage in adults is 10 mg administered as a single subcutaneous injection at least 30 minutes before the start of emetogenic chemotherapy on Day 1.

From the Dosage and Administration section of the FDA label we read for Granisetron — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

From our Q&A

Questions About Wild Lettuce or Granisetron

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

This page covers Wild Lettuce only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Granisetron page lists 38 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Lithium (major), 5-htp (moderate), Acetyl-l-carnitine (moderate) and Ayahuasca (moderate).

By severity: 2 major · 25 moderate · 11 minor.

From our pharmacist’s overview on the Granisetron page

“Granisetron (Kytril, Sustol) blocks serotonin signals to stop nausea from chemotherapy and surgery, and this is a list that warrants real caution before you add a supplement to it. Most of the entries raise serotonin themselves, and stacking them on a serotonin-acting drug can push toward serotonin syndrome, a dangerous overload of tha…”

Reviewed by 2 · Jul 18, 2026

Open the Granisetron interaction page

One more smart check

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

We hold 99 real supplement products containing Wild Lettuce, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Wild Lettuce. Even though Wild Lettuce itself has no known interaction with Granisetron, 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 Wild Lettuce and Granisetron 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 Wild Lettuce
Steady interest

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

29 days ago today
Medication Granisetron
Steady interest

#2,161 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 Wild Lettuce reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Wild Lettuce and Granisetron 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 Wild Lettuce

What is Wild Lettuce?

Wild Lettuce
  • Insomnia and trouble sleeping
  • Anxiety and restlessness
  • Pain relief
  • Cough and respiratory symptoms
  • Muscle spasms

Wild lettuce is a traditional herb used mainly for sleep, anxiety, and pain, but solid human research supporting these uses is very limited. Because its safety is not well studied, it should be used cautiously, avoided in pregnancy and breastfeeding, and discussed with your pharmacist or doctor first.

Lactuca virosa · Asteraceae · Leaves, dried milky sap (latex/lactucarium), and aerial parts · Capsules, tablets, dried herb, tea, tincture, extract, and smoking/vaping preparations

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

Wild Lettuce: dosing

There is no well-established or standardized dose for wild lettuce. The right amount can vary widely depending on the product, form (tea, capsule, tincture, or extract), and how it is prepared.Because a safe and effective dose has not been clearly defined in research, the best approach is to follow the directions on the product label and start with the lowest suggested amount.

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

Read the full Wild Lettuce monograph & all interactions
Medication

About Granisetron

What Is Granisetron Used For?

Brand names: Kytril, Sustol

Granisetron is used to prevent nausea and vomiting linked to emetogenic (nausea-causing) cancer chemotherapy — including high-dose cisplatin — and radiation therapy, including total body irradiation and fractionated abdominal radiation. Granisetron hydrochloride tablets and Granisol oral solution are approved for both the chemotherapy and radiation indications. Sancuso skin patch is approved for prevention of nausea and vomiting in adults receiving moderately and/or highly emetogenic chemotherapy regimens of up to 5 consecutive days.

Granisetron hydrochloride injection (intravenous) is also used to prevent and treat postoperative nausea and vomiting in adults. Sustol (subcutaneous injection) is used in combination with other anti-nausea medicines in adults specifically for the prevention of acute and delayed nausea and vomiting associated with moderately emetogenic chemotherapy or anthracycline and cyclophosphamide combination chemotherapy regimens.

See full Granisetron drug information
Keep checking

Other Drugs & Wild Lettuce

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

0Major
393Moderate
0Minor
2,436No known interaction
393 Moderate 2,436 No interaction
Moderate

393 interactions

Showing 60 of 393 moderate interactions — see all 393 on the Wild Lettuce page.

No interaction 2,436 drugs checked — show the list

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

Showing the 60 most looked-up of 2,436 medications checked with no known interaction — see the full Wild Lettuce list.

See the full Wild Lettuce interactions page
See every supplement checked against Granisetron, ranked by severity
Evidence & sources

Wild Lettuce References

The 5 references that drive our Wild Lettuce 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. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  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. Besharat S, Besharat M, Jabbari A. Wild lettuce (Lactuca virosa) toxicity. BMJ Case Rep. 2009;2009. pii: bcr06.2008.0134.
  5. Mullins ME, Horowitz BZ. The case of the salad shooters: intravenous injection of wild lettuce extract. Vet Hum Toxicol. 1998;40(5):290-1.

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 Wild Lettuce and Granisetron Together: Common Questions

Is it safe to take Wild Lettuce with Granisetron?
We do not list a known interaction between Wild Lettuce and Granisetron. 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 Wild Lettuce and Granisetron have any of the same side effects?
Yes — our sources link each of them separately to 9 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.
Should I take Wild Lettuce and Granisetron at the same time of day?
At least one FDA label for a product containing Granisetron says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Granisetron on its own and move Wild Lettuce to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.
How was the Wild Lettuce and Granisetron combination checked?
Interactions in our licensed database are recorded against drug classes. Granisetron is filed under 3 classifications, and Wild Lettuce has documented interactions with 2 drug classes — none of Granisetron'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 Wild Lettuce interact with any other medications?
Yes. Wild Lettuce has 393 documented drug interactions in our database — Granisetron 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 Granisetron interact with any supplements?
Yes. Granisetron has documented interactions with 38 supplements in our database — Wild Lettuce is not one of them. The Granisetron 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

Wild Lettuce monograph Uses, safety profile, and every drug interaction in one place Granisetron drug information The full plain-English guide to this medication Granisetron supplement interactions Every supplement checked against Granisetron, 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 5 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Granisetron and Wild Lettuce?

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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.