Drug & supplement interaction

Neem + 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 Neem 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

Neem 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 Neem 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.

Neem safety at a glance

Neem overall Use caution Leaf preparations are likely safe short-term for most adults, but neem oil and seed extracts can be toxic if swallowed.
Pregnancy Likely Unsafe When neem oil or leaf is used orally. Neem oil and leaf have been used as abortifacients. Read the full pregnancy detail
Breastfeeding Avoid There is not enough reliable safety information, so it is best avoided 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 Neem? 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. Neem has documented interactions with 7 drug classes — the most serious being antidiabetes drugs (moderate), cytochrome p450 1a2 (cyp1a2) substrates (moderate) and cytochrome p450 2c8 (cyp2c8) substrates (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

Neem Does Interact With Other Medications

Neem has 1,013 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 1,013 No known interaction 1,817 (incl. Cephalexin)
Taking anything else?

Check Another of Your Medications Against Neem

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

What to actually watch for

No Interaction Found — But Data Suggests Neem 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. 5 of them are worth acting on rather than waiting out — marked below.

  • Yellowing of the skin or eyes / Anemia Worth acting on Additional detail

    Neem

    “Orally, neem leaf has been reported to cause hemolysis in adults. In one case report, a 35-year-old male with diabetes and glucose-6-phosphate dehydrogenase (G6PD) deficiency developed hemolytic anemia and jaundice after drinking several liters of neem tea daily for 3 weeks. All symptoms resolved after discontinuation and supportive treatment.”

    Neem · Natural Medicines adverse-effect record, reported in anemia.

    6 sources cited
    1. 12835. Boeke SJ, Boersma MG, Alink GM, et al. Safety evaluation of neem (Azadirachta indica) derived pesticides. J Ethnopharmacol 2004;94:25-41. PubMed
    2. 94571. Page C, Hawes EM. Haemolytic anaemia after ingestion of Neem (Azadirachta indica) tea. BMJ Case Rep. 2013. pii: bcr2013200890.
    3. 3473. Sinniah D, Baskaran G. Margosa oil poisoning as a cause of Reye's syndrome. Lancet 1981;1:487-9. PubMed
    4. 3474. Sinniah D, Baskaran G, Looi LM, Leong KL. Reye-like syndrome due to margosa oil poisoning: report of a case with postmortem findings. Am J Gastroenterol 1982;77:158-61.
    5. 3476. Lai SM, Lim KW, Cheng HK. Margosa oil poisoning as a cause of toxic encephalopathy. Singapore Med J 1990;31:463-5.
    6. 64865. Sinniah, D., Sinniah, R., Baskaran, G., Pathmanathan, R., Yamashita, F., and Yoshino, M. Evaluation of the possible role of glucose, carnitine, coenzyme Q10 and steroids in the treatment of Reye's syndrome using the margosa oil animal model. Acta Paediat PubMed

    Cephalexin

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

  • Seizures Worth acting on Additional detail

    Neem

    “Orally, single doses of neem oil ranging from a few drops to 60 mL have been associated with reports of encephalopathy in infants and small children. Symptoms include drowsiness, seizure, loss of consciousness, coma, cerebral edema, Reye-like syndrome, and death within hours of ingestion. There is also at least one case report of neurotoxicity in an adult after ingestion of a neem-based pesticide.”

    Neem · Natural Medicines adverse-effect record, reported in epilepsy.

    6 sources cited
    1. 3473. Sinniah D, Baskaran G. Margosa oil poisoning as a cause of Reye's syndrome. Lancet 1981;1:487-9. PubMed
    2. 3474. Sinniah D, Baskaran G, Looi LM, Leong KL. Reye-like syndrome due to margosa oil poisoning: report of a case with postmortem findings. Am J Gastroenterol 1982;77:158-61.
    3. 3476. Lai SM, Lim KW, Cheng HK. Margosa oil poisoning as a cause of toxic encephalopathy. Singapore Med J 1990;31:463-5.
    4. 64855. Senanayake, M. P., Rupasinghe, S., and Dissanayake, P. V. Margosa (Kohomba) oil induced toxic encephalopathy following home remedy for intestinal worms. Ceylon Med.J 2009;54(4):140. PubMed
    5. 94750. Braidy N, Berg J, Clement J, et al. Role of nicotinamide dinucleotide and related precursors as therapeutic targets for age-related degenerative diseases: rationale, biochemistry, pharmacokinetics, and outcomes. Antiox Redox Signal 2018.
    6. 64858. Iyyadurai, R., Surekha, V., Sathyendra, S., Paul, Wilson B., and Gopinath, K. G. Azadirachtin poisoning: a case report. Clin Toxicol.(Phila) 2010;48(8):857-858. PubMed

    Cephalexin

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

  • Kidney problems Worth acting on Additional detail

    Neem

    “Orally, neem leaf has been reported to cause oliguria and anuria in adults. After a single intrauterine instillation, purified neem oil has been reported to cause endometritis in healthy, tubectomised females.”

    Neem · Natural Medicines adverse-effect record, reported in endometritis.

    3 sources cited
    1. 12833. Ibrahim IA, Khalid SA, Omer SA, Adam SE. On the toxicology of Azadirachta indica leaves. J Ethnopharmacol 1992;35:267-73. PubMed
    2. 12834. Ali BH. Toxicology of Azadirachta indica. J Ethnopharmacol 1994;42:71-2. PubMed
    3. 64886. Talwar, G. P., Pal, R., Singh, O., Garg, S., Taluja, V., Upadhyay, S. N., Gopalan, S., Jain, V., Kaur, J., and Sehgal, S. Safety of intrauterine administration of purified neem seed oil (Praneem Vilci) in women & effect of its co-administration with the

    Cephalexin

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

  • Liver problems Worth acting on Additional detail

    Neem

    Recorded for Neem in the same Natural Medicines adverse-effect record shown under Kidney problems above.

    Cephalexin

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

  • Diarrhea / Vomiting Additional detail

    Neem

    “Orally, neem oil has been reported to cause vomiting and loose stools in infants and small children.”

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

    4 sources cited
    1. 3473. Sinniah D, Baskaran G. Margosa oil poisoning as a cause of Reye's syndrome. Lancet 1981;1:487-9. PubMed
    2. 3474. Sinniah D, Baskaran G, Looi LM, Leong KL. Reye-like syndrome due to margosa oil poisoning: report of a case with postmortem findings. Am J Gastroenterol 1982;77:158-61.
    3. 3476. Lai SM, Lim KW, Cheng HK. Margosa oil poisoning as a cause of toxic encephalopathy. Singapore Med J 1990;31:463-5.
    4. 64865. Sinniah, D., Sinniah, R., Baskaran, G., Pathmanathan, R., Yamashita, F., and Yoshino, M. Evaluation of the possible role of glucose, carnitine, coenzyme Q10 and steroids in the treatment of Reye's syndrome using the margosa oil animal model. Acta Paediat PubMed

    Cephalexin

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

Reported for Neem but not commonly for Cephalexin: fainting, thoughts of self-harm, loss of vision and drowsiness.

Effects for Cephalexin come from the ADVERSE REACTIONS section of its FDA label; effects for Neem 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

Neem in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

When neem oil or leaf is used orally. Neem oil and leaf have been used as abortifacients.

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

From our Q&A

Questions About Neem 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 Neem 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 Neem 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 Neem as Part of a Dietary Supplement Product? Check It for Interactions

We hold 288 real supplement products containing Neem, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Neem. Even though Neem 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 Neem 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 Neem
Top half

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

29 days ago today
Medication Cephalexin
Top 5%

#69 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 Neem reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Neem 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 Neem

What is Neem?

Neem
  • Skin conditions
  • Dental and gum health
  • Antimicrobial and antiparasitic
  • Digestive upset
  • Blood sugar support
  • Insect repellent/pesticide

Neem is a tree from India used for centuries in traditional medicine, especially for skin, dental, and antimicrobial purposes. Some small studies are promising for oral health and skin, but high-quality human evidence is limited for most uses. Neem oil and seed extracts can be toxic if swallowed, especially in children, so use with caution and talk to your pharmacist or doctor first.

Azadirachta indica · Meliaceae · Leaves, seeds (and seed oil), bark, and twigs · Capsules, leaf powder, leaf extract, tea, topical oil, toothpaste, mouth rinse, and soap

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

Neem: dosing

There is no well-established standard dose for neem, and products vary widely in strength and form. Because of this, the safest approach is to follow the directions on the product label and not exceed the recommended amount.Topical products (like creams, soaps, and oils for the skin) and oral neem leaf supplements are used differently, so do not assume one form's instructions apply to another.

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

Read the full Neem 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 & Neem

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

0Major
1,013Moderate
0Minor
1,816No known interaction
1,013 Moderate 1,816 No interaction
Moderate

1,013 interactions

Showing 60 of 1,013 moderate interactions — see all 1,013 on the Neem page.

No interaction 1,816 drugs checked — show the list

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

Showing the 60 most looked-up of 1,816 medications checked with no known interaction — see the full Neem list.

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

Neem References

The 28 references that drive our Neem 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. Sinniah D, Baskaran G. Margosa oil poisoning as a cause of Reye's syndrome. Lancet 1981;1:487-9. PubMed
  2. Sinniah D, Baskaran G, Looi LM, Leong KL. Reye-like syndrome due to margosa oil poisoning: report of a case with postmortem findings. Am J Gastroenterol 1982;77:158-61.
  3. Sinniah R, Sinniah D, Chia LS, Baskaran G. Animal model of margosa oil ingestion with Reye-like syndrome. Pathogenesis of microvesicular fatty liver. J Pathol 1989;159:255-64. PubMed
  4. Lai SM, Lim KW, Cheng HK. Margosa oil poisoning as a cause of toxic encephalopathy. Singapore Med J 1990;31:463-5.
  5. Biswas K, Chattopadhyay I, Banerjee RK, Bandyopadhyay U. Biological activities and medicinal properties of neem (Azadirachta indica). Curr Sci 2002;82:1336-45.
  6. Upadhyay SN, Dhawan S, Garg S, Talwar GP. Immunomodulatory effects of neem (Azadirachta indica) oil. Int J Immunopharmacol 1992;14:1187-93. PubMed
  7. Ibrahim IA, Khalid SA, Omer SA, Adam SE. On the toxicology of Azadirachta indica leaves. J Ethnopharmacol 1992;35:267-73. PubMed
  8. Ali BH. Toxicology of Azadirachta indica. J Ethnopharmacol 1994;42:71-2. PubMed
  9. Boeke SJ, Boersma MG, Alink GM, et al. Safety evaluation of neem (Azadirachta indica) derived pesticides. J Ethnopharmacol 2004;94:25-41. PubMed
  10. Abdel-Ghaffar, F. and Semmler, M. Efficacy of neem seed extract shampoo on head lice of naturally infected humans in Egypt. Parasitol.Res 2007;100(2):329-332. PubMed
  11. Reutemann, P. and Ehrlich, A. Neem oil: an herbal therapy for alopecia causes dermatitis. Dermatitis 2008;19(3):E12-E15.
  12. Senanayake, M. P., Rupasinghe, S., and Dissanayake, P. V. Margosa (Kohomba) oil induced toxic encephalopathy following home remedy for intestinal worms. Ceylon Med.J 2009;54(4):140. PubMed
  13. Bhaskar, M. V., Pramod, S. J., Jeevika, M. U., Chandan, P. K., and Shetteppa, G. MR imaging findings of neem oil poisoning. AJNR Am J Neuroradiol. 2010;31(7):E60-E61.
  14. Iyyadurai, R., Surekha, V., Sathyendra, S., Paul, Wilson B., and Gopinath, K. G. Azadirachtin poisoning: a case report. Clin Toxicol.(Phila) 2010;48(8):857-858. PubMed
  15. Sinniah, D., Sinniah, R., Baskaran, G., Pathmanathan, R., Yamashita, F., and Yoshino, M. Evaluation of the possible role of glucose, carnitine, coenzyme Q10 and steroids in the treatment of Reye's syndrome using the margosa oil animal model. Acta Paediat 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 Neem and Cephalexin Together: Common Questions

Is it safe to take Neem with Cephalexin?
We do not list a known interaction between Neem 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 Neem and Cephalexin have any of the same side effects?
Yes — our sources link each of them separately to 7 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.
How was the Neem and Cephalexin combination checked?
Interactions in our licensed database are recorded against drug classes. Cephalexin is filed under 7 classifications, and Neem 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 Neem interact with any other medications?
Yes. Neem has 1,013 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 — Neem 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

Neem 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 28 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Cephalexin and Neem?

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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.