Drug & supplement interaction

Asian Water Plantain + Promethazine

Promethazine brand name: Phenergan.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 27, 2026
The bottom line No known interaction

We found no known interaction between Asian Water Plantain and Promethazine 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

Asian Water Plantain and Promethazine

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 Promethazine and Asian Water Plantain 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.

Asian Water Plantain safety at a glance

Asian Water Planta... overall Use caution Human safety data are limited, and high or long-term use may stress the kidneys or liver.
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.

Still wondering about combining Promethazine and Asian Water Plantain? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Promethazine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Promethazine is filed under 4 classifications — including phenothiazines, anticholinergic drugs, photosensitizing drugs. Asian Water Plantain has documented interactions with 1 drug class — the most serious being nephrotoxic drugs (minor) — and none of Promethazine’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

Asian Water Plantain Does Interact With Other Medications

Asian Water Plantain has 355 minor known drug interactions in our database — Promethazine isn’t one of them. If you take anything else, check it against the full list below.

Minor 355 No known interaction 2,475 (incl. Promethazine)
Taking anything else?

Check Another of Your Medications Against Asian Water Plantain

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

What to actually watch for

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

  • Bleeding or bruising Worth acting on Additional detail

    Asian Water Plantain

    “One case report of drug-induced systemic toxicity, including hepatotoxicity, has occurred in a 59-year-old man with chronic hepatitis B who had taken six doses of a combination product containing Asian water plantain 3 weeks prior to admission. He presented with gum bleed and petechiae, and his admission lab values indicated fulminant liver failure.”

    Asian Water Plantain · Natural Medicines adverse-effect record, reported in hepatitis.

    1 source cited
    1. 99434. Yuen MF, Tam S, Fung J, Wong DK, Wong BC, Lai CL. Traditional Chinese medicine causing hepatotoxicity in patients with chronic hepatitis B infection: a 1-year prospective study. Aliment Pharmacol Ther. 2006 Oct 15;24(8):1179-86. PubMed

    Promethazine

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

Reported for Asian Water Plantain but not commonly for Promethazine: liver problems and kidney problems.

Effects for Promethazine come from the ADVERSE REACTIONS section of its FDA label; effects for Asian Water Plantain come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 22,361 voluntary FDA FAERS reports for Promethazine 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.

From our Q&A

Questions About Asian Water Plantain or Promethazine

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

This page covers Asian Water Plantain only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Promethazine page lists 83 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Henbane (major), Scopolia (major), Alfalfa (moderate) and Angel's Trumpet (moderate).

By severity: 3 major · 57 moderate · 23 minor.

From our pharmacist’s overview on the Promethazine page

“Promethazine (Phenergan) is a phenothiazine antihistamine used for allergies, nausea, and motion sickness, and it is strongly anticholinergic on its own, causing dry mouth, blurred vision, drowsiness, and constipation. That is why the 83 supplements and herbs on this list deserve real attention, starting with the three rated major.”

Reviewed by 2 · Jul 18, 2026

Open the Promethazine interaction page

How much people look this up

Where Asian Water Plantain and Promethazine 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 Asian Water Plantain
Steady interest

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

29 days ago today
Medication Promethazine
Top half

#977 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 Asian Water Plantain reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 27, 2026. The Asian Water Plantain and Promethazine 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 Asian Water Plantain

What is Asian Water Plantain?

Asian Water Plantain
  • Promoting urination (diuretic)
  • Fluid retention and swelling
  • Urinary discomfort
  • Cholesterol and heart health support
  • Kidney and bladder support

Asian water plantain (Ze Xie) is a rhizome long used in traditional Chinese medicine, mainly as a diuretic and for fluid retention. Modern evidence is mostly limited to laboratory and animal studies, so its benefits in people are not well proven, and quality human safety data are lacking. Talk with a pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Alisma plantago-aquatica · Alismataceae · Dried rhizome (root-like stem), known as Rhizoma Alismatis or Ze Xie · Dried sliced rhizome, powders, decoctions (teas), capsules, and as part of multi-herb traditional Chinese medicine formulas

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

Asian Water Plantain: dosing

There is no well-established standardized dose for Asian water plantain as a supplement. In traditional Chinese medicine, the dried rhizome is typically used as part of a multi-herb formula prepared by a trained practitioner, not taken alone.If you use a commercial product, follow the directions on the label and do not exceed the recommended amount. Do not use it as a substitute for prescribed diuretics or other proven treatments.

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

Read the full Asian Water Plantain monograph & all interactions
Medication

About Promethazine

What Is Promethazine Used For?

Brand name: Phenergan

Promethazine is used for a wide range of conditions. Tablets, oral solution, and rectal suppositories (brands including Phenergan, Promethegan, and Phenadoz) are approved for seasonal and perennial allergic rhinitis, vasomotor rhinitis, allergic conjunctivitis, hives (urticaria), angioedema, dermographism, and allergic reactions to blood or plasma. They are also used for motion sickness (both prevention and active treatment), nausea and vomiting related to anesthesia and surgery, sedation, and as a helper medication alongside pain relievers after surgery.

Promethazine hydrochloride injection (brands including Phenergan and Promethazine HCl injection) is used for many of the same purposes but is reserved for situations where oral treatment is not possible — including allergic emergencies as an adjunct to epinephrine, sedation during labor, and as an aid during certain surgical procedures such as bronchoscopy and eye surgery.

Most-Reported Side Effects for Promethazine

From FAERS, the FDA’s public side-effect reporting system (22,614 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Dependence 3,586 reports
Nausea 2,646 reports
Vomiting 1,802 reports
Fatigue 1,496 reports
Diarrhea 1,341 reports
See full Promethazine drug information
Keep checking

Other Drugs & Asian Water Plantain

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

0Major
0Moderate
355Minor
2,474No known interaction
355 Minor 2,474 No interaction
Minor

355 interactions

Showing 60 of 355 minor interactions — see all 355 on the Asian Water Plantain page.

No interaction 2,474 drugs checked — show the list

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

Showing the 60 most looked-up of 2,474 medications checked with no known interaction — see the full Asian Water Plantain list.

See the full Asian Water Plantain interactions page
See every supplement checked against Promethazine, ranked by severity
Evidence & sources

Asian Water Plantain References

The 1 references that drive our Asian Water Plantain 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. Yuen MF, Tam S, Fung J, Wong DK, Wong BC, Lai CL. Traditional Chinese medicine causing hepatotoxicity in patients with chronic hepatitis B infection: a 1-year prospective study. Aliment Pharmacol Ther. 2006 Oct 15;24(8):1179-86. 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 Asian Water Plantain and Promethazine Together: Common Questions

Is it safe to take Asian Water Plantain with Promethazine?
We do not list a known interaction between Asian Water Plantain and Promethazine. 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 Asian Water Plantain and Promethazine 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.
How was the Asian Water Plantain and Promethazine combination checked?
Interactions in our licensed database are recorded against drug classes. Promethazine is filed under 4 classifications, and Asian Water Plantain has documented interactions with 1 drug class — none of Promethazine'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 Asian Water Plantain interact with any other medications?
Yes. Asian Water Plantain has 355 documented drug interactions in our database — Promethazine 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 Promethazine interact with any supplements?
Yes. Promethazine has documented interactions with 83 supplements in our database — Asian Water Plantain is not one of them. The Promethazine 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

Asian Water Plantain monograph Uses, safety profile, and every drug interaction in one place Promethazine drug information The full plain-English guide to this medication Promethazine supplement interactions Every supplement checked against Promethazine, 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 1 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Promethazine and Asian Water Plantain?

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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.