Drug & supplement interaction

Sassafras + Glycerol Phenylbutyrate

Glycerol Phenylbutyrate brand name: Ravicti.

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 Sassafras and Glycerol Phenylbutyrate 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 Glycerol Phenylbutyrate 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

Sassafras and Glycerol Phenylbutyrate

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 Glycerol Phenylbutyrate and Sassafras 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.

Sassafras safety at a glance

Sassafras overall Avoid Sassafras contains safrole, a compound linked to cancer and liver toxicity, and the FDA has banned it in food.
Pregnancy Likely Unsafe When used orally; avoid using. Sassafras oil has abortifacient effects. Read the full pregnancy detail
Breastfeeding Likely Unsafe When used orally; avoid using. Sassafras oil has abortifacient effects. Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Glycerol Phenylbutyrate and Sassafras? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Glycerol Phenylbutyrate

Interactions in our licensed database are recorded against drug classes, not just single drug names. Glycerol Phenylbutyrate is filed under a single classification — oral drugs. Sassafras has documented interactions with 2 drug classes — the most serious being cns depressants (moderate) and cytochrome p450 1a2 (cyp1a2) inducers (moderate) — and none of Glycerol Phenylbutyrate’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

Sassafras Does Interact With Other Medications

Sassafras has 275 moderate known drug interactions in our database — Glycerol Phenylbutyrate isn’t one of them. If you take anything else, check it against the full list below.

Moderate 275 No known interaction 2,555 (incl. Glycerol Phenylbutyrate)
Taking anything else?

Check Another of Your Medications Against Sassafras

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

What to actually watch for

No Interaction Found — But Data Suggests Sassafras and Glycerol Phenylbutyrate 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.

  • Vomiting reported in 12.2% of FDA reports for Glycerol Phenylbutyrate Additional detail

    Sassafras

    “Sassafras is generally regarded as unsafe for use in medicinal amounts. Any benefits of therapy may not outweigh the risks of toxicity. Orally, sassafras can cause diaphoresis and hot flashes (11). Consumption of large amounts of sassafras oil can cause hallucinations lasting for several days (4).”

    Sassafras · Natural Medicines adverse-effect record, reported in abortion.

    6 sources cited
    1. 11. 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. 4. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
    3. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
    4. 73138. Segelman, A. B., Segelman, F. P., Karliner, J., and Sofia, R. D. Sassafras and herb tea. Potential health hazards. JAMA 8-2-1976;236(5):477. DOI
    5. 73134. Ueng, Y. F., Hsieh, C. H., Don, M. J., Chi, C. W., and Ho, L. K. Identification of the main human cytochrome P450 enzymes involved in safrole 1'-hydroxylation. Chem Res Toxicol 2004;17(8):1151-1156. PubMed
    6. 73137. Kapadia, G. J., Chung, E. B., Ghosh, B., Shukla, Y. N., Basak, S. P., Morton, J. F., and Pradhan, S. N. Carcinogenicity of some folk medicinal herbs in rats. J Natl.Cancer Inst. 1978;60(3):683-686.

    “Orally, consuming 5 mL sassafras oil can cause vomiting (4,6).”

    Sassafras · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    2 sources cited
    1. 4. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
    2. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.

    Glycerol Phenylbutyrate

    Listed in the ADVERSE REACTIONS section of the FDA label for Glycerol Phenylbutyrate, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • A skin rash Additional detail

    Sassafras

    “Topically, sassafras can cause contact dermatitis (6).”

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

    1 source cited
    1. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.

    Glycerol Phenylbutyrate

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

Reported for Sassafras but not commonly for Glycerol Phenylbutyrate: hallucinations, raised blood pressure, a fast or pounding heartbeat and sweating.

Effects for Glycerol Phenylbutyrate come from the ADVERSE REACTIONS section of its FDA label; effects for Sassafras come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 1,358 voluntary FDA FAERS reports for Glycerol Phenylbutyrate 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.

Special populations

Sassafras in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Unsafe

When used orally; avoid using. Sassafras oil has abortifacient effects.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

How to take them

Some Glycerol Phenylbutyrate Products Have a Food Rule — Sassafras Should Not Break It

At least one FDA label for a product containing Glycerol Phenylbutyrate says to take it with food. If you take Sassafras on an empty stomach out of habit, keep them separate — and take Glycerol Phenylbutyrate 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 Glycerol Phenylbutyrate 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.

Instruct patients to take glycerol phenylbutyrate oral liquid with food or formula and to administer directly into the mouth via oral syringe.

From the Dosage and Administration section of the FDA label we read for Glycerol Phenylbutyrate — 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.

Everything else you take

See Every Supplement That Interacts With Glycerol Phenylbutyrate

This page covers Sassafras only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Glycerol Phenylbutyrate page lists 17 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Glucomannan (moderate) and Guar Gum (moderate).

By severity: 1 major · 7 moderate · 9 minor.

From our pharmacist’s overview on the Glycerol Phenylbutyrate page

“Ravicti (glycerol phenylbutyrate) pulls ammonia out of the blood in people with urea cycle disorders, so a dose that never gets absorbed is not a small problem, it can let ammonia climb toward dangerous levels. That is why this list deserves real attention even though it is short.”

Reviewed by 2 · Jul 18, 2026

Open the Glycerol Phenylbutyrate interaction page

One more smart check

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

We hold 11 real supplement products containing Sassafras, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Sassafras. Even though Sassafras itself has no known interaction with Glycerol Phenylbutyrate, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Sassafras and Glycerol Phenylbutyrate 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 Sassafras
Top half

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

29 days ago today
Medication Glycerol Phenylbutyrate
Top 10%

#162 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 Sassafras reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 27, 2026. The Sassafras and Glycerol Phenylbutyrate 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 Sassafras

What is Sassafras?

  • Digestive complaints
  • Cold and flu symptoms
  • Joint and muscle aches
  • Skin conditions (topical folk use)
  • As a flavoring agent (traditional root beer)

Sassafras is an aromatic North American tree whose root bark and oil were once popular in teas and as a flavoring, but it contains safrole, a compound the FDA has banned in foods because it can cause cancer and liver damage. There is no good evidence it safely treats any health condition, and most experts recommend avoiding internal use. If you want the flavor, choose products that are labeled safrole-free.

Sassafras albidum · Lauraceae · Root bark, bark, and essential oil · Tea, dried root bark, essential oil, capsules, and as a flavoring

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

Sassafras: dosing

There is no established safe dose for sassafras, and most experts recommend not taking it internally at all because of safrole. There is no standardized medical dosing.If you use a commercial flavoring product that is labeled safrole-free, follow the directions on the label. Do not use whole sassafras root, bark, or essential oil as a home remedy.

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

Read the full Sassafras monograph & all interactions
Medication

About Glycerol Phenylbutyrate

What Is Glycerol Phenylbutyrate Used For?

Brand name: Ravicti

Glycerol phenylbutyrate oral liquid — available as the brand Ravicti and as a generic — is used for the long-term (chronic) management of urea cycle disorders (UCDs). UCDs are rare inherited conditions where the body cannot properly convert ammonia into urea, causing toxic ammonia levels to build up in the blood and brain.

It is used in patients whose ammonia cannot be controlled by a low-protein diet and/or amino acid supplements alone. It must always be used alongside dietary protein restriction and, in some cases, additional dietary supplements such as essential amino acids, arginine, or citrulline. It is not for treating a sudden, severe spike in ammonia (acute hyperammonemia), and its safety and effectiveness for N-acetylglutamate synthase (NAGS) deficiency have not been established.

See full Glycerol Phenylbutyrate drug information
Keep checking

Other Drugs & Sassafras

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

0Major
275Moderate
0Minor
2,554No known interaction
275 Moderate 2,554 No interaction
Moderate

275 interactions

Showing 60 of 275 moderate interactions — see all 275 on the Sassafras page.

No interaction 2,554 drugs checked — show the list

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

Showing the 60 most looked-up of 2,554 medications checked with no known interaction — see the full Sassafras list.

See the full Sassafras interactions page
See every supplement checked against Glycerol Phenylbutyrate, ranked by severity
Evidence & sources

Sassafras References

The 9 references that drive our Sassafras 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. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  2. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  3. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
  4. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  5. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  6. Ueng, Y. F., Hsieh, C. H., Don, M. J., Chi, C. W., and Ho, L. K. Identification of the main human cytochrome P450 enzymes involved in safrole 1'-hydroxylation. Chem Res Toxicol 2004;17(8):1151-1156. PubMed
  7. Kapadia, G. J., Chung, E. B., Ghosh, B., Shukla, Y. N., Basak, S. P., Morton, J. F., and Pradhan, S. N. Carcinogenicity of some folk medicinal herbs in rats. J Natl.Cancer Inst. 1978;60(3):683-686.
  8. Segelman, A. B., Segelman, F. P., Karliner, J., and Sofia, R. D. Sassafras and herb tea. Potential health hazards. JAMA 8-2-1976;236(5):477. DOI
  9. Hu L, Wu F, He J, Zhong L, Song Y, Shao H. Cytotoxicity of safrole in HepaRG cells: studies on the role of CYP1A2-mediated ortho-quinone metabolic activation. Xenobiotica. 2019;49(12):1504-1515. 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 Sassafras and Glycerol Phenylbutyrate Together: Common Questions

Is it safe to take Sassafras with Glycerol Phenylbutyrate?
We do not list a known interaction between Sassafras and Glycerol Phenylbutyrate. 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 Sassafras and Glycerol Phenylbutyrate have any of the same side effects?
Yes — our sources link each of them separately to 2 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 Sassafras and Glycerol Phenylbutyrate at the same time of day?
At least one FDA label for a product containing Glycerol Phenylbutyrate says to take it with food. If you take Sassafras on an empty stomach out of habit, keep them separate and take Glycerol Phenylbutyrate with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Glycerol Phenylbutyrate products can differ — so check the directions on your own box. This is about absorption, not an interaction.
How was the Sassafras and Glycerol Phenylbutyrate combination checked?
Interactions in our licensed database are recorded against drug classes. Glycerol Phenylbutyrate is filed under 1 classification, and Sassafras has documented interactions with 2 drug classes — none of Glycerol Phenylbutyrate'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 Sassafras interact with any other medications?
Yes. Sassafras has 275 documented drug interactions in our database — Glycerol Phenylbutyrate 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 Glycerol Phenylbutyrate interact with any supplements?
Yes. Glycerol Phenylbutyrate has documented interactions with 17 supplements in our database — Sassafras is not one of them. The Glycerol Phenylbutyrate 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

Sassafras monograph Uses, safety profile, and every drug interaction in one place Glycerol Phenylbutyrate drug information The full plain-English guide to this medication Glycerol Phenylbutyrate supplement interactions Every supplement checked against Glycerol Phenylbutyrate, 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 9 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Glycerol Phenylbutyrate and Sassafras?

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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.