Drug & supplement interaction

Indian Snakeroot + Diphenhydramine, Pseudoephedrine

Diphenhydramine, Pseudoephedrine brand name: Actifed Allergy.

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

Diphenhydramine, Pseudoephedrine falls into 2 drug categories that Indian Snakeroot can interact with; the most serious is rated moderate. Theoretically, taking Indian snakeroot might cause additive sedative effects.

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

Indian Snakeroot and Diphenhydramine, Pseudoephedrine

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

Why Are There 2 Interactions?

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

Moderate

CNS DEPRESSANTS

1 of 2

Why this applies to Diphenhydramine, Pseudoephedrine

Diphenhydramine, Pseudoephedrine falls under CNS DEPRESSANTS — the group Indian Snakeroot interacts with.

Theoretically, taking Indian snakeroot might cause additive sedative effects.
Sedation and drowsiness have been reported in clinical trials using Indian snakeroot.
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 thing to keep an eye on with Actifed Allergy. This product is a combo: diphenhydramine is a sedating antihistamine (the same drug in many nighttime sleep aids), and pseudoephedrine is a decongestant that can actually be a little stimulating. Indian snakeroot, thanks to its reserpine content, has its own calming, drowsy-making effect.

So when you pair the snakeroot with the diphenhydramine half, the sleepy effects can stack up. You might feel more groggy, foggy, or unsteady than expected, which matters before driving. Reserpine can also lower blood pressure, so dizziness is worth watching. This is mostly a theoretical concern based on how these act, not strong proof. Still, please run it by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sheldon MB, Kotte JH. Effect of Rauwolfia serpentina and reserpine on the blood pressure in essential hypertension; a long-term double-blind study. Circulation. 1957 Aug;16(2):200-6.
  2. Vakil RJ. A clinical trial of Rauwolfia serpentina in essential hypertension. Br Heart J. 1949 Oct;11(4):350-5. PubMed
  3. Achor RW, Hanson NO, Gifford RW Jr. Hypertension treated with Rauwolfia serpentina (whole root) and with reserpine; controlled study disclosing occasional severe depression. J Am Med Assoc. 1955 Oct 29;159(9):841-5. PubMed
  4. Wilkins RW, Judson WE. The use of Rauwolfia serpentina in hypertensive patients. N Engl J Med. 1953 Jan 8;248(2):48-53.
Moderate

STIMULANT DRUGS

2 of 2

Diphenhydramine, Pseudoephedrine also falls under STIMULANT DRUGS.

Theoretically, concomitant use might cause additive effects.
Yohimbine, a constituent of Indian snakeroot, has sympathomimetic effects and increases blood pressure in a dose-dependent manner. Theoretically, taking Indian snakeroot with stimulant drugs can have additive stimulant and hypertensive 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 situation with this allergy combo, which pairs the antihistamine diphenhydramine with the decongestant pseudoephedrine. Pseudoephedrine is a stimulant that can already nudge your blood pressure and heart rate up. The concern on file is that certain compounds in Indian snakeroot may add their own stimulating, pressure-raising push on top of that. In theory, stacking them could mean more jitteriness, a faster or pounding heartbeat, and higher blood pressure than you'd get from the decongestant alone.

I want to be straight with you: this warning is theoretical, based on how the ingredients behave rather than solid human studies, so it may never cause a problem for you. Still, Indian snakeroot is a potent herb, so please check with your pharmacist or doctor before combining them, especially if you have high blood pressure or heart issues.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
  2. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  3. Bharucha AE, Skaar T, Andrews CN, et al Relationship of cytochrome P450 pharmacogenetics to the effects of yohimbine on gastrointestinal transit and catecholamines in healthy subjects. Neurogastroenterol Motil. 2008;20(8):891-9. 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

Indian Snakeroot Also Interacts With Other Medications

Indian Snakeroot has 83 major, 759 moderate known drug interactions in our database — the Diphenhydramine, Pseudoephedrine one above is among them. If you take anything else, check it against the full list below.

Major 83 Moderate 759 No known interaction 1,988 (incl. Diphenhydramine, Pseudoephedrine)
Taking anything else?

Check Another of Your Medications Against Indian Snakeroot

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

Everything else you take

See Every Supplement That Interacts With Diphenhydramine, Pseudoephedrine

This page covers Indian Snakeroot only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Diphenhydramine, Pseudoephedrine page lists 185 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Beer (major), Ephedra (major) and Gamma-hydroxybutyrate (ghb) (major).

By severity: 13 major · 150 moderate · 22 minor.

From our pharmacist’s overview on the Diphenhydramine, Pseudoephedrine page

“This medicine pulls in two directions at once, which is exactly why the supplement list for diphenhydramine and pseudoephedrine (Actifed Allergy) is not one to skim. The antihistamine half is sedating, so anything else that slows the brain deepens drowsiness; beer, wine, and kava all carry major ratings, with alcohol the best documented.”

Reviewed by 2 · Jul 18, 2026

Open the Diphenhydramine, Pseudoephedrine interaction page

One more smart check

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

We hold 70 real supplement products containing Indian Snakeroot, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Indian Snakeroot. Your product may carry other ingredients that interact with Diphenhydramine, Pseudoephedrine too, on top of Indian Snakeroot — 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 Indian Snakeroot and Diphenhydramine, Pseudoephedrine 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 Indian Snakeroot
Top half

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

29 days ago today
Medication Diphenhydramine, Pseudoephedrine
Steady interest

#1,707 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 Indian Snakeroot

What is Indian Snakeroot?

Indian Snakeroot
  • High blood pressure
  • Anxiety and stress
  • Insomnia
  • Agitation
  • Fever (traditional use)

Indian snakeroot is a traditional Ayurvedic plant that contains reserpine, a compound with real blood-pressure-lowering and sedative effects. Because its potent alkaloids can cause serious side effects like depression and very low blood pressure, it should never be used without medical supervision. It is not a safe or simple home remedy, and many countries restrict its use.

Read the full Indian Snakeroot monograph & all interactions
Keep checking

Other Drugs & Indian Snakeroot

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

83Major
759Moderate
0Minor
1,987No known interaction
83 Major 759 Moderate 1,987 No interaction
Major

83 interactions

Showing 60 of 83 major interactions — see all 83 on the Indian Snakeroot page.

Moderate

759 interactions

Showing 60 of 759 moderate interactions — see all 759 on the Indian Snakeroot page.

No interaction 1,987 drugs checked — show the list

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

Showing the 60 most looked-up of 1,987 medications checked with no known interaction — see the full Indian Snakeroot list.

See the full Indian Snakeroot interactions page
See every supplement checked against Diphenhydramine, Pseudoephedrine, 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
Indian Snakeroot monograph › Uses, safety, and every drug interaction in one place Diphenhydramine, Pseudoephedrine supplement interactions › Every supplement checked against Diphenhydramine, Pseudoephedrine, 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 Indian Snakeroot and Diphenhydramine, Pseudoephedrine Together: Common Questions

Can you take Indian Snakeroot with Diphenhydramine, Pseudoephedrine?
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 Indian Snakeroot and Diphenhydramine, Pseudoephedrine?
Diphenhydramine, Pseudoephedrine belongs to more than one drug category, and Indian Snakeroot 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 Indian Snakeroot and Diphenhydramine, Pseudoephedrine 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.