Drug & supplement interaction

Citronella Oil + Cephalexin

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

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Citronella Oil 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.

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Interaction report

Citronella Oil 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 Citronella Oil 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Citronella Oil at all — not against Cephalexin, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Citronella Oil safety at a glance

Citronella Oil overall Use caution Generally safe for topical and aromatic use, but it can irritate skin and should never be swallowed.
Pregnancy Use caution Limited safety data; use only sparingly on skin or in the air and check with your doctor first.
Breastfeeding Use caution Not well studied; avoid applying near the breast and consult your doctor before use.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Cephalexin and Citronella Oil? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Citronella Oil Itself Has Been Linked To

This is not an interaction — nothing below involves Cephalexin. It is the side-effect record for Citronella Oil on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Citronella Oil, this list is the first place to look.

  • A skin rash Additional detail

    “Topically, citronella oil is thought to be a skin sensitizer and can potentially cause contact dermatitis. Applying citronella oil 100% to the skin causes irritation or a burning sensation in about 12% of people.”

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

    2 sources cited
    1. 13084. Public Health Agency of Canada. Safety Tips on Using Personal Insect Repellents Available at: http://www.phac-aspc.gc.ca/wn-no/repellents-insectifuge_e.html. (Accessed 24 May 2005)
    2. 97274. Sajo ME, Song SB, Bajgai J, et al. Applicability of citronella oil (Cymbopogon winteratus) for the prevention of mosquito-borne diseases in the rural area of Tikapur, far-western Nepal. Rural Remote Health 2015;15(4):3532. Epub 2015 Nov 12. DOI

Everything above comes from the Natural Medicines adverse-effect record for Citronella Oil — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Cephalexin’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Cephalexin column appears here.

From our Q&A

Questions About Citronella Oil 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 Citronella Oil 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 Citronella Oil 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

How much people look this up

Where Citronella Oil 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 Citronella Oil
Steady interest

#1,431 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Cephalexin
Top 5%

#93 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 Citronella Oil reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Citronella Oil and Cephalexin 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 Citronella Oil

What is Citronella Oil?

  • Insect and mosquito repellent
  • Aromatherapy and relaxation
  • Topical antimicrobial
  • Fragrance in soaps and household products
  • Skin and hair care products

Citronella oil is an essential oil made from a tropical grass and is best known as a natural insect repellent. Some evidence supports short-term mosquito protection, but it usually does not last as long as conventional repellents like DEET. It is meant for skin or air use, not for swallowing, and can irritate sensitive skin.

Cymbopogon nardus · Poaceae · Leaves and grass (steam-distilled essential oil) · Essential oil, sprays, lotions, candles, diffuser oil

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

Citronella Oil: dosing

There is no official standardized dose for citronella oil. For skin use, it is usually diluted with a carrier oil (such as coconut or almond oil) in commercial repellent products. For aromatherapy, a few drops are added to a diffuser or warm water.Because product strengths vary widely, the best approach is to follow the directions on the label and reapply repellent products as instructed.

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

Read the full Citronella Oil 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 & Citronella Oil

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Citronella Oil list.

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

Citronella Oil References

The 5 references that drive our Citronella Oil 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. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
  2. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  3. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
  4. Public Health Agency of Canada. Safety Tips on Using Personal Insect Repellents Available at: http://www.phac-aspc.gc.ca/wn-no/repellents-insectifuge_e.html. (Accessed 24 May 2005)
  5. Sajo ME, Song SB, Bajgai J, et al. Applicability of citronella oil (Cymbopogon winteratus) for the prevention of mosquito-borne diseases in the rural area of Tikapur, far-western Nepal. Rural Remote Health 2015;15(4):3532. Epub 2015 Nov 12. DOI

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 Citronella Oil and Cephalexin Together: Common Questions

Is it safe to take Citronella Oil with Cephalexin?
We do not list a known interaction between Citronella Oil 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.
Does Cephalexin interact with any supplements?
Yes. Cephalexin has documented interactions with 61 supplements in our database — Citronella Oil 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

Citronella Oil 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 5 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Cephalexin and Citronella Oil?

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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.