Drug & supplement interaction

Eastern Hemlock + Quinine

Quinine brand name: Qualaquin.

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 Eastern Hemlock and Quinine 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 Quinine 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

Eastern Hemlock and Quinine

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 Quinine and Eastern 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 Eastern Hemlock at all — not against Quinine, 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.

Eastern Hemlock safety at a glance

Eastern Hemlock overall Use caution Little modern safety data exists, and the essential oil can be irritating, so use carefully.
Pregnancy Avoid Not enough safety information is available, so it is best avoided.
Breastfeeding Avoid Safety has not been studied, so avoid use while breastfeeding.

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

Still wondering about combining Quinine and Eastern Hemlock? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Eastern Hemlock and Quinine 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. 2 of them are worth acting on rather than waiting out — marked below.

  • Kidney problems Worth acting on Additional detail

    Eastern Hemlock

    “Orally, no adverse effects have been reported. However, a thorough evaluation of safety outcomes has not been conducted. Eastern hemlock bark is rich in tannins. Plants with at least 10% tannins may cause gastrointestinal disturbances, kidney damage, and necrotic conditions of the liver.”

    Eastern Hemlock · Natural Medicines adverse-effect record, reported in allergic rhinitis (hay fever).

    2 sources cited
    1. 12. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
    2. 48525. Mitchell, J. C. Patch test results - screening set and plants. Contact Dermatitis Newsletter 1970;8:177.

    Quinine

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

  • An allergic reaction Worth acting on Additional detail

    Eastern Hemlock

    “Topically, allergic reaction to eastern hemlock has been rarely reported. In a study of 125 forest workers, one developed contact dermatitis. The individual showed a positive patch test reaction to an extract of Eastern hemlock.”

    Eastern Hemlock · Natural Medicines adverse-effect record, reported in dermatitis.

    1 source cited
    1. 48525. Mitchell, J. C. Patch test results - screening set and plants. Contact Dermatitis Newsletter 1970;8:177.

    Quinine

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

  • Stomach upset Additional detail

    Eastern Hemlock

    Recorded for Eastern Hemlock in the same Natural Medicines adverse-effect record shown under Kidney problems above.

    Quinine

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

  • A skin rash Additional detail

    Eastern Hemlock

    Recorded for Eastern Hemlock in the same Natural Medicines adverse-effect record shown under An allergic reaction above.

    Quinine

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

Effects for Quinine come from the ADVERSE REACTIONS section of its FDA label; effects for Eastern 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.

How to take them

Some Quinine Products Have a Food Rule — Eastern Hemlock Should Not Break It

At least one FDA label for a product containing Quinine says to take it with food. If you take Eastern Hemlock on an empty stomach out of habit, keep them separate — and take Quinine with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Quinine 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.

Quinine sulfate capsules should be taken with food to minimize gastric upset [see Clinical Pharmacology (12.3) ] .

From the Dosage and Administration section of the FDA label we read for Quinine — 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 Eastern Hemlock or Quinine

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

This page covers Eastern Hemlock only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Quinine page lists 175 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Cinchona (major), Foxglove (major), Grapefruit (major) and Lily-of-the-valley (major).

By severity: 9 major · 125 moderate · 41 minor.

From our pharmacist’s overview on the Quinine page

“Quinine (Qualaquin) earns a genuine pause before you add any supplement, because nine of its 175 interacting ingredients are rated major, and two are as everyday as grapefruit and St. John's wort.”

Reviewed by 2 · Jul 18, 2026

Open the Quinine interaction page

How much people look this up

Where Eastern Hemlock and Quinine 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 Eastern Hemlock
Steady interest

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

29 days ago today
Medication Quinine
Steady interest

#2,070 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 Eastern Hemlock reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Eastern Hemlock and Quinine 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 Eastern Hemlock

What is Eastern Hemlock?

  • Coughs and colds
  • Sore throat
  • Wound care
  • Vitamin C source (needle tea)
  • Aches and pains (topical)

Eastern Hemlock is an evergreen conifer tree (Tsuga canadensis) traditionally used by Native Americans and early settlers for coughs, sore throats, and as a vitamin C-rich tea. There is very little modern scientific evidence to support any of these uses, and it should not be confused with poison hemlock. Talk to a pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Tsuga canadensis · Pinaceae · Inner bark, needles (leaves), young twigs, and resin · Tea, tincture, essential oil, salve, and bark extract

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

Eastern Hemlock: dosing

There is no established or standardized dose for Eastern Hemlock. It has not been studied enough to know a safe and effective amount for any condition.If you choose to use a commercial product, follow the directions on the label exactly and do not exceed them. Essential oils should be used only as directed for external use and kept away from the eyes, mouth, and children.

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

Read the full Eastern Hemlock monograph & all interactions
Medication

About Quinine

What Is Quinine Used For?

Brand name: Qualaquin

Quinine sulfate capsules (brands Qualaquin and Quinine Sulfate) are approved to treat uncomplicated Plasmodium falciparum malaria in adults. This includes strains of malaria that have become resistant to chloroquine.

Quinine sulfate capsules are not approved for severe or complicated malaria, for preventing malaria, or for treating or preventing nocturnal leg cramps. Using them for leg cramps carries serious risks that outweigh any potential benefit.

See full Quinine drug information
Keep checking

Other Drugs & Eastern Hemlock

Browse every other medication we’ve checked against Eastern 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 Eastern 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 Eastern Hemlock list.

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

Eastern Hemlock References

The 2 references that drive our Eastern 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. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Mitchell, J. C. Patch test results - screening set and plants. Contact Dermatitis Newsletter 1970;8:177.

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 Eastern Hemlock and Quinine Together: Common Questions

Is it safe to take Eastern Hemlock with Quinine?
We do not list a known interaction between Eastern Hemlock and Quinine. 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 Eastern Hemlock and Quinine have any of the same side effects?
Yes — our sources link each of them separately to 4 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 Eastern Hemlock and Quinine at the same time of day?
At least one FDA label for a product containing Quinine says to take it with food. If you take Eastern Hemlock on an empty stomach out of habit, keep them separate and take Quinine with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Quinine products can differ — so check the directions on your own box. This is about absorption, not an interaction.
Does Quinine interact with any supplements?
Yes. Quinine has documented interactions with 175 supplements in our database — Eastern Hemlock is not one of them. The Quinine 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

Eastern Hemlock monograph Uses, safety profile, and every drug interaction in one place Quinine drug information The full plain-English guide to this medication Quinine supplement interactions Every supplement checked against Quinine, 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 2 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Quinine and Eastern 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.