Drug & supplement interaction

Baikal Skullcap + Fexofenadine

Fexofenadine brand name: Allegra.

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

Fexofenadine falls into 2 drug categories that Baikal Skullcap can interact with; the most serious is rated minor. Theoretically, Baikal skullcap might increase levels of drugs transported by P-glycoprotein.

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

Baikal Skullcap and Fexofenadine

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

Why Are There 2 Interactions?

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

Minor

P-GLYCOPROTEIN SUBSTRATES

1 of 2

Why this applies to Fexofenadine

Fexofenadine falls under P-GLYCOPROTEIN SUBSTRATES — the group Baikal Skullcap interacts with.

Theoretically, Baikal skullcap might increase levels of drugs transported by P-glycoprotein.
In vitro and animal research suggests that baicalein, oroxylin A, and wogonin, constituents of Baikal skullcap, can inhibit P-glycoprotein. This effect has not been reported in humans.
Severity Minor 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 Allegra (fexofenadine). Your body relies on a tiny pump called P-glycoprotein to move fexofenadine in and out of cells, and it strongly affects how much of the drug you actually absorb. Lab and animal studies hint that compounds in Baikal skullcap (baicalein, wogonin, and others) can slow that pump down. If that happened in people, a bit more fexofenadine could stick around, which might mean slightly stronger antihistamine effects or a touch more drowsiness or headache.

The honest part: this is theoretical. It has only been seen in test tubes and animals, never confirmed in humans, and it's rated a minor interaction. Fexofenadine itself is a very gentle medicine. Still, if you plan to take concentrated skullcap supplements regularly, run it by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Lee, Y., Yeo, H., Liu, S. H., Jiang, Z., Savizky, R. M., Austin, D. J., and Cheng, Y. C. Increased anti-P-glycoprotein activity of baicalein by alkylation on the A ring. J Med Chem 10-21-2004;47(22):5555-5566. PubMed
  2. Lee, E., Enomoto, R., Suzuki, C., Ohno, M., Ohashi, T., Miyauchi, A., Tanimoto, E., Maeda, K., Hirano, H., Yokoi, T., and Sugahara, C. Wogonin, a plant flavone, potentiates etoposide-induced apoptosis in cancer cells. Ann N Y Acad Sci 2007;1095:521-526. PubMed
  3. Go, W. J., Ryu, J. H., Qiang, F., and Han, H. K. Evaluation of the flavonoid oroxylin A as an inhibitor of P-glycoprotein-mediated cellular efflux. J Nat Prod 2009;72(9):1616-1619. PubMed
  4. Enomoto, R., Koshiba, C., Suzuki, C., and Lee, E. Wogonin potentiates the antitumor action of etoposide and ameliorates its adverse effects. Cancer Chemother.Pharmacol 2011;67(5):1063-1072. PubMed
Minor

ORGANIC ANION-TRANSPORTING POLYPEPTIDE SUBSTRATES (OATP)

2 of 2

Fexofenadine also falls under ORGANIC ANION-TRANSPORTING POLYPEPTIDE SUBSTRATES (OATP).

Theoretically, Baikal skullcap might alter the levels and clinical effects of OATP substrates.
Some pharmacokinetic research shows that baicalin, a constituent of Baikal skullcap, can decrease plasma levels of rosuvastatin. The mechanism is thought to involve stimulation of the activity of the organic anion-transporting polypeptide 1B1 (OATP1B1), which transports rosuvastatin into the liver. This decreases plasma levels of the drug, but increases levels at the site of action in the liver. The degree to which rosuvastatin levels are affected depends on the OATP1B1 haplotype of the individual. Baikal skullcap might also affect other OATP1B1 substrates.
Severity Minor Likelihood Possible Evidence B

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 with Allegra (fexofenadine) and Baikal skullcap. Fexofenadine isn't really broken down by liver enzymes. Instead, it relies on transporter proteins (including OATP) to move in and out of your body. Some early research suggests baicalin, a compound in this herb, can nudge those OATP transporters to work harder. In theory, that could pull a little more fexofenadine out of your bloodstream, which might make your allergy relief feel slightly weaker, so a runny nose or itchy eyes could creep back.

Honestly though, this is mostly lab and limited human data, mainly studied with a cholesterol drug, not fexofenadine. The effect is rated minor. If you take both and notice your allergy symptoms aren't well controlled, just mention it to your pharmacist or doctor before changing anything.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Fan L, Zhang W, Guo D, et al. The effect of herbal medicine baicalin on pharmacokinetics of rosuvastatin, substrate of organic anion-transporting polypeptide 1B1. Clin Pharmacol Ther 2007;83:471-6. PubMed
  2. Chen C, Mireles RJ, Campbell SD, et al. Differential interaction of 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors with ABCB1, ABCC2, and OATP1B1. Drug Metab Dispos 2005;33:537-46. PubMed
  3. Pasanen MK, Fredrikson H, Neuvonen PJ, Niemi M. Different effects of SLCO1B1 polymorphism on the pharmacokinetics of atorvastatin and rosuvastatin. Clin Pharmacol Ther 2007;82:726-33. PubMed
  4. Konig J, Seithel A, Gradhand U, Fromm MF. Pharmacogenomics of human OATP transporters. Naunyn-Schmiedeberg Arch Pharmacol 2006;372:432-43. 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

Baikal Skullcap Also Interacts With Other Medications

Baikal Skullcap has 594 moderate, 351 minor known drug interactions in our database — the Fexofenadine one above is among them. If you take anything else, check it against the full list below.

Moderate 594 Minor 351 No known interaction 1,885 (incl. Fexofenadine)
Taking anything else?

Check Another of Your Medications Against Baikal Skullcap

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

From our Q&A

Questions About Baikal Skullcap or Fexofenadine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Baikal Skullcap or Fexofenadine, 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 Fexofenadine

This page covers Baikal Skullcap only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fexofenadine page lists 154 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Apple (major), Grapefruit (major), St. John's Wort (major) and Sweet Orange (major).

By severity: 5 major · 111 moderate · 38 minor.

From our pharmacist’s overview on the Fexofenadine page

“An over-the-counter allergy pill sounds like the last place serious interactions would hide, but fexofenadine (Allegra) has 154 supplements and foods on file, and the five rated major deserve real attention before you combine it with much of anything else. Two of those five sit in most refrigerators.”

Reviewed by 2 · Jul 18, 2026

Open the Fexofenadine interaction page

One more smart check

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

We hold 737 real supplement products containing Baikal Skullcap, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Baikal Skullcap. Your product may carry other ingredients that interact with Fexofenadine too, on top of Baikal Skullcap — 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 Baikal Skullcap and Fexofenadine 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 Baikal Skullcap
Top 25%

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

29 days ago today
Medication Fexofenadine
Top half

#823 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 Baikal Skullcap

What is Baikal Skullcap?

Baikal Skullcap
  • Inflammation
  • Allergies
  • Anxiety and sleep
  • Immune support
  • Respiratory infections

Baikal skullcap is a traditional Chinese herb (Huang Qin) used for inflammation, allergies, and infections, with active compounds like baicalin and baicalein studied mostly in the lab. Human evidence remains limited, so it should not replace proven treatments. Talk to your pharmacist or doctor before using it, and avoid it in pregnancy and breastfeeding.

Read the full Baikal Skullcap monograph & all interactions
Medication

About Fexofenadine

What Is Fexofenadine Used For?

Brand name: Allegra

Fexofenadine temporarily relieves symptoms of hay fever (seasonal allergic rhinitis) and other upper respiratory allergies, including runny nose, sneezing, itchy or watery eyes, and itching of the nose or throat.

Several products — including Allegra Hives 24hr tablets — are specifically used to reduce hives (urticaria) and relieve the itching that comes with them. Keep in mind that fexofenadine will not prevent hives or stop an allergic skin reaction from happening in the first place.

See full Fexofenadine drug information
Keep checking

Other Drugs & Baikal Skullcap

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

0Major
594Moderate
351Minor
1,884No known interaction
594 Moderate 351 Minor 1,884 No interaction
Moderate

594 interactions

Showing 60 of 594 moderate interactions — see all 594 on the Baikal Skullcap page.

Minor

351 interactions

Showing 60 of 351 minor interactions — see all 351 on the Baikal Skullcap page.

No interaction 1,884 drugs checked — show the list

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

Showing the 60 most looked-up of 1,884 medications checked with no known interaction — see the full Baikal Skullcap list.

See the full Baikal Skullcap interactions page
See every supplement checked against Fexofenadine, 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
Baikal Skullcap monograph › Uses, safety, and every drug interaction in one place Fexofenadine supplement interactions › Every supplement checked against Fexofenadine, ranked by severity Fexofenadine drug information › The full plain-English guide to this medication 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 Baikal Skullcap and Fexofenadine Together: Common Questions

Can you take Baikal Skullcap with Fexofenadine?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 2 interactions listed for Baikal Skullcap and Fexofenadine?
Fexofenadine belongs to more than one drug category, and Baikal Skullcap 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 Baikal Skullcap and Fexofenadine interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Fexofenadine and Baikal Skullcap?

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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.