Drug & supplement interaction

Gravel Root + Belladonna, Phenobarbital

Belladonna, Phenobarbital brand names: Bellophen, Susano.

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

Gravel Root has a moderate interaction with Belladonna, Phenobarbital. Hepatotoxic pyrrolizidine alkaloids (PA) are substrates of cytochrome P450 3A4 (CYP3A4).

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

Gravel Root and Belladonna, Phenobarbital

Here is the interaction we found between these two, with the evidence behind it.

Moderate

CYTOCHROME P450 3A4 (CYP3A4) INDUCERS

Why this applies to Belladonna, Phenobarbital

Belladonna, Phenobarbital falls under CYTOCHROME P450 3A4 (CYP3A4) INDUCERS — the group Gravel Root interacts with.

Hepatotoxic pyrrolizidine alkaloids (PA) are substrates of cytochrome P450 3A4 (CYP3A4). Theoretically, drugs that induce CYP3A4 might increase the conversion of PAs to toxic metabolites. Some drugs that induce CYP3A4 include carbamazepine (Tegretol), phenobarbital, phenytoin (Dilantin), rifampin, rifabutin (Mycobutin), and others.
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 know about combining Gravel Root with a product like Bellophen or Susano. The phenobarbital in these medicines is a strong CYP3A4 inducer, meaning it revs up a liver enzyme. Gravel Root contains pyrrolizidine alkaloids, which that same enzyme can turn into liver-damaging byproducts. So in theory, speeding up that enzyme could mean Gravel Root gets converted into more toxic compounds, raising the chance of liver stress.

I'll be straight with you: this concern comes from lab and animal data, not real human studies, so it's more of a caution than a proven danger. Still, Gravel Root already has a shaky safety record for the liver, so I'd avoid pairing it with phenobarbital. Please check with your pharmacist or doctor before using it.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Chojkier M. Hepatic sinusoidal-obstruction syndrome: toxicity of pyrrolizidine alkaloids. J Hepatol 2003;39:437-46. PubMed
  2. Wang YP, Yan J, Fu PP, Chou MW. Human liver microsomal reduction of pyrrolizidine alkaloid N-oxides to form the corresponding carcinogenic parent alkaloid. Toxicol Lett 2005;155:411-20. 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

Gravel Root Also Interacts With Other Medications

Gravel Root has 87 moderate known drug interactions in our database — the Belladonna, Phenobarbital one above is one of them. If you take anything else, check it against the full list below.

Moderate 87 No known interaction 2,743 (incl. Belladonna, Phenobarbital)
Taking anything else?

Check Another of Your Medications Against Gravel Root

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

Everything else you take

See Every Supplement That Interacts With Belladonna, Phenobarbital

This page covers Gravel Root only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Belladonna, Phenobarbital page lists 174 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), Gamma-hydroxybutyrate (ghb) (major) and Henbane (major).

By severity: 10 major · 143 moderate · 21 minor.

From our pharmacist’s overview on the Belladonna, Phenobarbital page

“Alcohol is the interaction I would flag first for anyone taking Belladonna and Phenobarbital (Bellophen, Susano). It carries a major, well-documented risk of deepened sedation, and it has plenty of company: 78 of the 174 supplements and herbs on file add drowsiness to a barbiturate that sedates on its own, kava among the worst of them.”

Reviewed by 2 · Jul 18, 2026

Open the Belladonna, Phenobarbital interaction page

One more smart check

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

We hold 20 real supplement products containing Gravel Root, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Gravel Root. Your product may carry other ingredients that interact with Belladonna, Phenobarbital too, on top of Gravel Root — 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 Gravel Root and Belladonna, Phenobarbital 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 Gravel Root
Steady interest

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

29 days ago today
Medication Belladonna, Phenobarbital
Top half

#911 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 Gravel Root

What is Gravel Root?

  • Kidney stones
  • Urinary tract complaints
  • Fluid retention
  • Gout and joint pain
  • Bladder irritation

Gravel Root is a traditional North American herb long used by herbalists for kidney stones and urinary problems, but there is very little modern scientific evidence to support these uses. Because it contains compounds that may harm the liver and its safety is poorly studied, it should be used with caution, if at all, and avoided in pregnancy and breastfeeding.

Read the full Gravel Root monograph & all interactions
Keep checking

Other Drugs & Gravel Root

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

0Major
87Moderate
0Minor
2,742No known interaction
87 Moderate 2,742 No interaction
Moderate

87 interactions

Showing 60 of 87 moderate interactions — see all 87 on the Gravel Root page.

No interaction 2,742 drugs checked — show the list

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

Showing the 60 most looked-up of 2,742 medications checked with no known interaction — see the full Gravel Root list.

See the full Gravel Root interactions page
See every supplement checked against Belladonna, Phenobarbital, 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
Gravel Root monograph › Uses, safety, and every drug interaction in one place Belladonna, Phenobarbital supplement interactions › Every supplement checked against Belladonna, Phenobarbital, 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 Gravel Root and Belladonna, Phenobarbital Together: Common Questions

Can you take Gravel Root with Belladonna, Phenobarbital?
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.
How serious is the Gravel Root and Belladonna, Phenobarbital 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.