Drug & supplement interaction

Coriander + Guanethidine, Hydrochlorothiazide

Guanethidine, Hydrochlorothiazide brand name: Esimil.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Guanethidine, Hydrochlorothiazide falls into 2 drug categories that Coriander can interact with; the most serious is rated moderate. Theoretically, coriander might increase the risk of hypotension when taken with antihypertensive drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Coriander and Guanethidine, Hydrochlorothiazide

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Coriander interacts with whole categories of medication. Guanethidine, Hydrochlorothiazide falls into 2 of those categories, so it can interact with Coriander in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

ANTIHYPERTENSIVE DRUGS

1 of 2

Why this applies to Guanethidine, Hydrochlorothiazide

Guanethidine, Hydrochlorothiazide falls under ANTIHYPERTENSIVE DRUGS — the group Coriander interacts with.

Theoretically, coriander might increase the risk of hypotension when taken with antihypertensive drugs.
Evidence from animal research suggests that coriander fruit can lower blood pressure.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Esimil pairs guanethidine, a strong blood pressure lowering drug, with hydrochlorothiazide, a water pill. Both already work to bring your blood pressure down. The idea here is that coriander, based only on early animal research, might also nudge blood pressure a little lower. Stacked on top of a medicine this powerful, that extra dip could leave you feeling dizzy, lightheaded, faint when you stand up quickly, or unusually tired.

Keep in mind this is theoretical and comes from lab and animal studies, not people. The sprinkle of cilantro on your tacos is very unlikely to matter. Concentrated extracts or essential oils are a different story, so check with your pharmacist or doctor before using those.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Jabeen, Q., Bashir, S., Lyoussi, B., and Gilani, A. H. Coriander fruit exhibits gut modulatory, blood pressure lowering and diuretic activities. J Ethnopharmacol. 2-25-2009;122(1):123-130. PubMed
Moderate

PHOTOSENSITIZING DRUGS

2 of 2

Guanethidine, Hydrochlorothiazide also falls under PHOTOSENSITIZING DRUGS.

Theoretically, coriander might increase the risk of photosensitivity when taken with photosensitizing drugs.
Evidence from in vitro research suggests that coriandrin, a constituent of coriander, has photosensitizing effects.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the gist for Esimil (which combines guanethidine with the water pill hydrochlorothiazide). The hydrochlorothiazide part is already known to make some people's skin more sensitive to sunlight, so they sunburn faster than usual. Coriander, especially as a concentrated extract or essential oil, contains a compound called coriandrin that may add a little to that sun sensitivity. So the concern is simply a higher chance of burning, redness, or a rash on sun-exposed skin.

I want to be honest about the evidence here. This is mostly theoretical and comes from lab studies, not real patient reports, so it's nothing to panic over. Coriander as a cooking herb in your food is very unlikely to matter. If you use coriander supplements, just wear sunscreen and check with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Ashwood-Smith, M. J., Warrington, P. J., Jenkins, M., Ceska, O., and Romaniuk, P. J. Photobiological properties of a novel, naturally occurring furoisocoumarin, coriandrin. Photochem.Photobiol. 1989;50(6):745-751. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Coriander Also Interacts With Other Medications

Coriander has 716 moderate known drug interactions in our database — the Guanethidine, Hydrochlorothiazide one above is among them. If you take anything else, check it against the full list below.

Moderate 716 No known interaction 2,114 (incl. Guanethidine, Hydrochlorothiazide)
Taking anything else?

Check Another of Your Medications Against Coriander

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

Everything else you take

See Every Supplement That Interacts With Guanethidine, Hydrochlorothiazide

This page covers Coriander only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Guanethidine, Hydrochlorothiazide page lists 231 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Asarabacca (major) and Dolomite (major).

By severity: 10 major · 196 moderate · 25 minor.

From our pharmacist’s overview on the Guanethidine, Hydrochlorothiazide page

“Guanethidine with hydrochlorothiazide (Esimil) lowers blood pressure two ways at once, and 231 supplement and herbal ingredients on file can interfere with it, ten rated major and just 25 minor, so treat this page with genuine care. Most of the 196 moderate entries pile extra blood-pressure-lowering on top of the drug, and a second lar…”

Reviewed by 2 · Jul 18, 2026

Open the Guanethidine, Hydrochlorothiazide interaction page

One more smart check

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

We hold 934 real supplement products containing Coriander, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Coriander. Your product may carry other ingredients that interact with Guanethidine, Hydrochlorothiazide too, on top of Coriander — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Coriander and Guanethidine, Hydrochlorothiazide 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 Coriander
Top 25%

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

29 days ago today
Medication Guanethidine, Hydrochlorothiazide
Steady interest

#1,668 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.

Supplement

About Coriander

What is Coriander?

Coriander
  • Digestive upset and gas
  • Appetite stimulation
  • Mild antimicrobial (topical)
  • Diarrhea and IBS symptoms
  • General flavoring and traditional remedy

Coriander (also called cilantro) is a common cooking herb and spice that has long been used in traditional medicine for digestive complaints. As a food it is generally safe for most people, but high-quality human studies supporting its medicinal benefits are limited. Talk with your pharmacist or doctor before using concentrated extracts or essential oils.

Read the full Coriander monograph & all interactions
Keep checking

Other Drugs & Coriander

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

0Major
716Moderate
0Minor
2,113No known interaction
716 Moderate 2,113 No interaction
Moderate

716 interactions

Showing 60 of 716 moderate interactions — see all 716 on the Coriander page.

No interaction 2,113 drugs checked — show the list

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

Showing the 60 most looked-up of 2,113 medications checked with no known interaction — see the full Coriander list.

See the full Coriander interactions page
See every supplement checked against Guanethidine, Hydrochlorothiazide, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Coriander monograph › Uses, safety, and every drug interaction in one place Guanethidine, Hydrochlorothiazide supplement interactions › Every supplement checked against Guanethidine, Hydrochlorothiazide, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Coriander and Guanethidine, Hydrochlorothiazide Together: Common Questions

Can you take Coriander with Guanethidine, Hydrochlorothiazide?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 2 interactions listed for Coriander and Guanethidine, Hydrochlorothiazide?
Guanethidine, Hydrochlorothiazide belongs to more than one drug category, and Coriander interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Coriander and Guanethidine, Hydrochlorothiazide interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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.