Drug & supplement interaction

Peony + Cephalexin

Cephalexin brand names: Keflex, Keftab, Cephalex, Lexin.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Peony and Cephalexin 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 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

Peony and Cephalexin

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 Cephalexin and Peony 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.

Peony safety at a glance

Peony overall Use caution Generally considered well tolerated for short-term use, but high-quality safety data are limited.
Pregnancy Possibly Unsafe When used orally. Preliminary research suggests that peony can cause uterine contractions. However, other preliminary research suggests a combination of peony a... Read the full pregnancy detail
Breastfeeding Avoid There is not enough reliable information to consider it safe while breastfeeding.

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 Cephalexin and Peony? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Cephalexin

Interactions in our licensed database are recorded against drug classes, not just single drug names. Cephalexin is filed under 7 classifications — including organic anion transporter 3 (oat3) substrates, organic anion transporter 1 (oat1) substrates, antibiotic drugs. Peony has documented interactions with 7 drug classes — the most serious being anticoagulant/antiplatelet drugs (moderate), clozapine (clozaril) (moderate) and contraceptive drugs (moderate) — and none of Cephalexin’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

Peony Does Interact With Other Medications

Peony has 811 moderate known drug interactions in our database — Cephalexin isn’t one of them. If you take anything else, check it against the full list below.

Moderate 811 No known interaction 2,019 (incl. Cephalexin)
Taking anything else?

Check Another of Your Medications Against Peony

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

What to actually watch for

No Interaction Found — But Data Suggests Peony and Cephalexin 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. One of them is worth acting on rather than waiting out — marked below.

  • Bleeding or bruising Worth acting on Additional detail

    Peony

    “Orally, there is one case report of easy gum bleeding, epistaxis, and skin bruising with an international normalized ratio (INR) above 6 in a 61-year-old male who was previously stable on warfarin therapy. This patient had switched from one brand of quilinggao, a popular Chinese herbal product, to another brand 5 days prior. This product contained Fritillaria spp.”

    Peony · Natural Medicines adverse-effect record, reported in bleeding.

    1 source cited
    1. 68343. Wong, A. L. and Chan, T. Y. Interaction between warfarin and the herbal product quilinggao. Ann Pharmacother 2003;37(6):836-838.

    Cephalexin

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

  • Stomach upset / Diarrhea / Nausea Additional detail

    Peony

    “Orally, peony and total glucosides of peony (TGP) have been reported to cause gastrointestinal discomfort, including abdominal distension, anorexia, diarrhea, and nausea, in some patients. In one clinical study, diarrhea was reported in 5% of patients taking TGP 600 mg three times daily for 24 weeks versus 1% of patients taking placebo.”

    Peony · Natural Medicines adverse-effect record, reported in anorexia.

    5 sources cited
    1. 13538. Anon. Monograph. Peony (Paeonia spp). Alt Med Rev 2001;6:495-9.
    2. 92785. Cai Y, Yuan Q, Xu K, et al. Assessment of the therapeutic effect of total glycosides of peony for juvenile idiopathic arthritis: a systematic review and meta-analysis. Evid Based Complement Alternat Med 2016;2016:8292486.
    3. 97949. Zhou Y, Jin L, Kong F, et al. Clinical and immunological consequences of total glucosides of paeony treatment in Sjögren's syndrome: A randomized controlled pilot trial. Int Immunopharmacol. 2016 Oct;39:314-319. doi: 10.1016/j.intimp.2016.08.006. PubMed
    4. 98466. Zhu Q, Qi X, Wu Y, Wang K. Clinical study of total glucosides of paeony for the treatment of diabetic kidney disease in patients with diabetes mellitus. Int Urol Nephrol. 2016 Nov;48(11):1873-1880. doi: 10.1007/s11255-016-1345-5. PubMed
    5. 100992. Liu X, Li X, Li X, et al. The efficacy and safety of total glucosides of peony in the treatment of primary Sjögren's syndrome: a multi-center, randomized, double-blinded, placebo-controlled clinical trial. Clin Rheumatol. 2019;38(3):657-64. Erratum i

    Cephalexin

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

Reported for Peony but not commonly for Cephalexin: bloating or gas, a skin rash and reduced appetite.

Effects for Cephalexin come from the ADVERSE REACTIONS section of its FDA label; effects for Peony come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Peony in Pregnancy & Breastfeeding

Pregnancy Possibly Unsafe

When used orally. Preliminary research suggests that peony can cause uterine contractions. However, other preliminary research suggests a combination of peony and angelica with or without motherwort, banksias rose, and ligustica, might be safe. Until more is known, avoid use.

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

Overlapping uses

What Cephalexin Is Prescribed For, and What Peony Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Cephalexin is a prescription medicine with approved uses on its FDA label. Peony is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Cephalexin is prescribed for: Cephalexin treats bacterial infections caused by susceptible strains of bacteria. It is used for respiratory tract infections, ear infections (otitis media), skin and skin structure infections, bone infections, and genitourinary tract infections — including acute prostatitis. It works only against bacterial infections — not viruses like colds or flu. Your prescriber should use it only when a bacterial infection is confirmed or strongly suspected, to help prevent antibiotic resistance.

Peony has been studied for:

  • Respiratory tract infections studied, not established Peony has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Peony for respiratory tract infections

    Although there has been interest in using oral peony for respiratory tract infections, there is insufficient reliable information about the clinical effects of peony for this purpose.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Cephalexin on your own; if you are taking Peony for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Peony or Cephalexin

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

This page covers Peony only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Cephalexin page lists 61 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Siberian Cocklebur (major), African Wild Potato (moderate) and Aristolochia (moderate).

By severity: 3 major · 47 moderate · 11 minor.

From our pharmacist’s overview on the Cephalexin page

“Cephalexin (Keflex) is one of the most commonly prescribed oral antibiotics, usually for skin and urinary infections, and its supplement list warrants genuine care rather than a quick skim. Three of the 61 ingredients on file rate major.”

Reviewed by 2 · Jul 18, 2026

Open the Cephalexin interaction page

One more smart check

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

We hold 71 real supplement products containing Peony, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Peony. Even though Peony itself has no known interaction with Cephalexin, 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 Peony and Cephalexin 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 Peony
Top 25%

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

29 days ago today
Medication Cephalexin
Top 5%

#67 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 Peony reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Peony and Cephalexin records this page draws on were last updated July 11, 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 Peony

What is Peony?

Peony
  • Menstrual cramps and irregular periods
  • Muscle cramps and spasms
  • Anxiety and stress
  • Inflammation and pain
  • Polycystic ovary syndrome (PCOS)

Peony root is a traditional Chinese medicine herb often used for menstrual problems, cramps, and inflammation, frequently as part of combination formulas. Human evidence for most uses is limited or preliminary, so it should not replace proven treatments. Talk to your pharmacist or doctor before using it, especially if you are pregnant, breastfeeding, or taking other medicines.

Paeonia lactiflora · Paeoniaceae · Root (and sometimes the root bark, flower, and seeds) · Dried root, powders, capsules, tinctures, teas, and combination herbal formulas

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

Peony: dosing

There is no well-established standardized dose for peony. The amount used varies depending on the form (dried root, powder, capsule, tincture, or tea) and whether it is used alone or in a combination formula.The safest approach is to follow the directions on the product label and to choose products from reputable manufacturers.

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

Read the full Peony monograph & all interactions
Medication

About Cephalexin

What Is Cephalexin Used For?

Brand names: Keflex, Keftab, Cephalex, Lexin

Cephalexin treats bacterial infections caused by susceptible strains of bacteria. It is used for respiratory tract infections, ear infections (otitis media), skin and skin structure infections, bone infections, and genitourinary tract infections — including acute prostatitis.

It works only against bacterial infections — not viruses like colds or flu. Your prescriber should use it only when a bacterial infection is confirmed or strongly suspected, to help prevent antibiotic resistance.

Most-Reported Side Effects for Cephalexin

From FAERS, the FDA’s public side-effect reporting system (0 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Chronic kidney disease 2,157 reports
Renal failure 1,558 reports
Acute kidney injury 1,550 reports
Diarrhea 1,405 reports
Fatigue 1,303 reports
See full Cephalexin drug information
Keep checking

Other Drugs & Peony

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

0Major
811Moderate
0Minor
2,018No known interaction
811 Moderate 2,018 No interaction
Moderate

811 interactions

Showing 60 of 811 moderate interactions — see all 811 on the Peony page.

No interaction 2,018 drugs checked — show the list

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

Showing the 60 most looked-up of 2,018 medications checked with no known interaction — see the full Peony list.

See the full Peony interactions page
See every supplement checked against Cephalexin, ranked by severity
Evidence & sources

Peony References

The 15 references that drive our Peony 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. Chen LC, Chou MH, Lin MF, Yang LL. Effects of Paeoniae Radix, a traditional Chinese medicine, on the pharmacokinetics of phenytoin. J Clin Pharm Ther 2001;26:271-8. PubMed
  2. Guo TL, Zhou XW. [Clinical observations on the treatment of the gestational hypertension syndrome with Angelica and Paeonia powder]. Zhong Xi Yi Jie He Za Zhi 1986;6:714-6, 707.
  3. Xie HJ, Yasar U, Sandberg M, Rane A. Paeoniae Radix, a traditional Chinese medicine, and CYP2C9 activity. J Clin Pharm Ther 2002;27:229-30. . PubMed
  4. Harada M, Suzuki M, Ozaki Y. Effect of Japanese Angelica root and peony root on uterine contraction in the rabbit in situ. J Pharmacobiodyn 1984;7:304-11. PubMed
  5. Anon. Monograph. Peony (Paeonia spp). Alt Med Rev 2001;6:495-9.
  6. Bruynzeel DP. Contact Dermatitis Due to Paeonia (Peony). Contact Dermatitis 1989; 20:152-3..
  7. Bian, X., Xu, Y., Zhu, L., Gao, P., Liu, X., Liu, S., Qian, M., Gai, M., Yang, J., and Wu, Y. Prevention of maternal-fetal blood group incompatibility with traditional Chinese herbal medicine. Chin Med J (Engl.) 1998;111(7):585-587.
  8. Wong, A. L. and Chan, T. Y. Interaction between warfarin and the herbal product quilinggao. Ann Pharmacother 2003;37(6):836-838.
  9. Cai Y, Yuan Q, Xu K, et al. Assessment of the therapeutic effect of total glycosides of peony for juvenile idiopathic arthritis: a systematic review and meta-analysis. Evid Based Complement Alternat Med 2016;2016:8292486.
  10. Koo YK, Kim JM, Koo JY, et al. Platelet anti-aggregatory and blood anti-coagulant effects of compounds isolated from Paeonia lactiflora and Paeonia suffruticosa. Pharmazie 2010;65(8):624-8.
  11. Wang W, Tian DD, Zheng B, et al. Peony-glycyrrhiza decoction, an herbal preparation, inhibits clozapine metabolism via cytochrome P450s, but not flavin-containing monooxygenase in in vitro models. Drug Metab Dispos 2015;43(7):1147-53. PubMed
  12. Zhou Y, Jin L, Kong F, et al. Clinical and immunological consequences of total glucosides of paeony treatment in Sjögren's syndrome: A randomized controlled pilot trial. Int Immunopharmacol. 2016 Oct;39:314-319. doi: 10.1016/j.intimp.2016.08.006. PubMed
  13. Zhu Q, Qi X, Wu Y, Wang K. Clinical study of total glucosides of paeony for the treatment of diabetic kidney disease in patients with diabetes mellitus. Int Urol Nephrol. 2016 Nov;48(11):1873-1880. doi: 10.1007/s11255-016-1345-5. PubMed
  14. Xu Y, Li X, Chen T, et al. Radix Paeoniae Alba increases serum estrogen level and up-regulates estrogen receptor expression in uterus and vagina of immature/ovariectomized mice. Phytother Res. 2019;33(1):117-29. [RETRACTED].
  15. Liu X, Li X, Li X, et al. The efficacy and safety of total glucosides of peony in the treatment of primary Sjögren's syndrome: a multi-center, randomized, double-blinded, placebo-controlled clinical trial. Clin Rheumatol. 2019;38(3):657-64. Erratum i

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 Peony and Cephalexin Together: Common Questions

Is it safe to take Peony with Cephalexin?
We do not list a known interaction between Peony and Cephalexin. 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 Peony and Cephalexin have any of the same side effects?
Yes — our sources link each of them separately to 4 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.
Are Peony and Cephalexin used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Peony in each. That is a conversation for your prescriber, especially if Cephalexin is being adjusted to a target.
How was the Peony and Cephalexin combination checked?
Interactions in our licensed database are recorded against drug classes. Cephalexin is filed under 7 classifications, and Peony has documented interactions with 7 drug classes — none of Cephalexin'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 Peony interact with any other medications?
Yes. Peony has 811 documented drug interactions in our database — Cephalexin 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 Cephalexin interact with any supplements?
Yes. Cephalexin has documented interactions with 61 supplements in our database — Peony is not one of them. The Cephalexin 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

Peony monograph Uses, safety profile, and every drug interaction in one place Cephalexin drug information The full plain-English guide to this medication Cephalexin supplement interactions Every supplement checked against Cephalexin, 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 15 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Cephalexin and Peony?

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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.