Medication interaction hub

What Supplements Interact with Cephalexin?

Cephalexin brand names: Keflex, Keftab, Cephalex, Lexin. Every interaction below applies to the brands too.

61 Interactions 3 Major 47 Moderate 11 Minor
Curated & coded by · Clinical Pharmacist · Updated September 22, 2026

Drug–supplement interaction data sourced from Natural Medicines Pro, the licensed clinical database from TRC Healthcare / Therapeutic Research, with additional analysis by the HelloPharmacist Pharmacist Team. Our sources · Editorial policy

What is this page for?

One answer, for one medication: what supplements and herbal products interact with Cephalexin? Every vitamin, herb, and supplement ingredient we’ve checked against it is on this page, ranked by severity, each linking to the full report for that exact pair.

This page covers supplement interactions only — to check Cephalexin against your other medications, use the drug–drug interaction checker. Educational information from our licensed clinical databases, not medical advice. Our editorial policy

HelloPharmacist Bottom Line
Our Pharmacist Explains
What is this? The interaction data in the HelloPharmacist supplement database is licensed from Natural Medicines Pro by TRC Healthcare (Therapeutic Research). HelloPharmacist pharmacists often add our own analysis and context on top of that licensed data — such as this Bottom Line summary and the notes on individual interaction pages — and any such commentary is noted as ours.

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. Two of those, Siberian cocklebur and asarabacca, can stress the kidneys, the same organ cephalexin depends on to clear from the body. The third, activated charcoal, can soak up the antibiotic before it reaches the bloodstream and leave an infection undertreated.

Most of the rest is gentler. Nearly half the list is probiotics, which the antibiotic can simply kill off, blunting their benefit, and another cluster of fiber and charcoal products can reduce absorption of anything swallowed. Spacing those well apart from your dose solves most of it. Of the 61 entries, 47 rate moderate and 11 minor; the kidney pairings are the ones capable of lasting harm.

— , Clinical Pharmacist · July 18, 2026

Major 3 Moderate 47 Minor 11 No known interaction 1,391

This box checks one ingredient at a time (like turmeric or magnesium). Taking a supplement product with a whole label of ingredients? Search the product instead — we check every ingredient on it ↓

Top Ingredient Interactions

Cephalexin: Top Interactions at a Glance

The most significant Cephalexin supplement & herbal interactions, colored by severity. Tap any ingredient to open the full report for that pair.

Showing the 12 highest-ranked of 61 interacting ingredients — plus 1,391 more checked with no known interaction. See the complete ranked list.

Start here

The Major Interactions to Know About

The most clinically significant Cephalexin + supplement combinations in our database, best-documented first. Open any card for the full report.

Major Likelihood Likely Siberian Cocklebur + Cephalexini

Siberian cocklebur can adversely affect the kidney.

Read the full interaction Major Likelihood Probable Activated Charcoal + Cephalexini

Activated charcoal reduces systemic exposure to many drugs, including those that undergo enterohepatic recirculation, regardless of the route of administration.

Read the full interaction Major Likelihood Possible Asarabacca + Cephalexini

Asarabacca, a herbaceous plant, is often contaminated with aristolochic acid, a compound known for its nephrotoxic effects.

Read the full interaction
The complete list

Every Supplement Checked Against Cephalexin

All 1,452 ingredients in our database, ranked by severity — 61 with a Cephalexin interaction on file and 1,391 with none found. Filter by severity or search any ingredient; hover the for what each ingredient is.

Looking for an interaction with a specific supplement product? Search products instead ↓

Straight answers

Can You Take It With Cephalexin?

One-line answers, one card per combination — scroll through today’s 20 and tap any card for the full report. A different set rotates in daily until every combination has had its turn.

Can you take Zinc with Cephalexin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Zinc might decrease cephalexin levels by chelating with cephalexin in the gut and preventing its absorption.

Full Zinc + Cephalexin answer

Can you take Dendrobium with Cephalexin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. The dendrobium constituent dendrobine is reported to have convulsant effects.

Full Dendrobium + Cephalexin answer

Can you take Flaxseed with Cephalexin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, antibiotics might interfere with the metabolism of flaxseed constituents, which could potentially alter the effects of flaxse...

Full Flaxseed + Cephalexin answer

Can you take Ginkgo with Cephalexin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking ginkgo with drugs that lower the seizure threshold might increase the risk for convulsions.

Full Ginkgo + Cephalexin answer

Can you take Guar Gum with Cephalexin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Guar gum might reduce the absorption of some oral drugs, potentially decreasing their effectiveness.

Full Guar Gum + Cephalexin answer

Can you take Gum Arabic with Cephalexin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, gum arabic can alter the absorption of oral drugs due to its fiber content.

Full Gum Arabic + Cephalexin answer

Can you take Melatonin with Cephalexin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking melatonin with drugs that lower the seizure threshold might increase the risk of seizure activity.

Full Melatonin + Cephalexin answer

Can you take Mountain Ash with Cephalexin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Taking large amounts of fresh mountain ash berries may cause kidney damage due to its parasorbic acid constituent.

Full Mountain Ash + Cephalexin answer

Can you take Quercetin with Cephalexin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, concomitant use might increase the effects and adverse effects of OAT3 substrates.

Full Quercetin + Cephalexin answer

Can you take Rauwolscine with Cephalexin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking rauwolscine with seizure threshold lowering drugs might increase the risk of adverse convulsant effects.

Full Rauwolscine + Cephalexin answer

Can you take Rhubarb with Cephalexin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, long-term use of anthraquinones from rhubarb might increase the risk of nephrotoxicity when used with nephrotoxic drugs.

Full Rhubarb + Cephalexin answer

Can you take Slippery Elm with Cephalexin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, slippery elm may slow the absorption and reduce serum levels of oral drugs.

Full Slippery Elm + Cephalexin answer

Can you take Thuja with Cephalexin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Thuja products can contains significant amounts of thujone, a neurotoxin.

Full Thuja + Cephalexin answer

Can you take Tragacanth with Cephalexin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, tragacanth might alter absorption of oral drugs.

Full Tragacanth + Cephalexin answer

Can you take Thyroid Extract with Cephalexin?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Food and medications can interfere with thyroid hormone absorption.

Full Thyroid Extract + Cephalexin answer

Can you take Agar with Cephalexin?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Agar forms a thick gel, which may disrupt the absorption of nutrients and medications.

Full Agar + Cephalexin answer

Can you take Algin with Cephalexin?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, algin can alter the absorption of oral drugs.

Full Algin + Cephalexin answer

Can you take Black Psyllium with Cephalexin?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.

Full Black Psyllium + Cephalexin answer

Can you take Blond Psyllium with Cephalexin?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.

Full Blond Psyllium + Cephalexin answer

Can you take Carob with Cephalexin?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Theoretically, carob might also impair the absorption of oral drugs.

Full Carob + Cephalexin answer
Read the list like a pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

  • Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
  • Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
  • Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
  • No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

  • Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
  • Probable. Interaction 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.
  • Possible. 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
  • Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

  • Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
  • Each entry links to a full report with the clinical detail, likelihood, evidence level, and citations for that exact combination.
  • Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

How Does Our Interaction Checker Work?

Behind every verdict on this page is a category system. Our source database doesn’t document supplement interactions drug-by-drug — it documents them against groups of medications that behave the same way (for example, “drugs processed by the CYP3A4 liver enzyme” or “blood-thinning medications”).

So the check works in three steps: (1) Cephalexin is classified into the pharmacology categories it belongs to, (2) every supplement interaction documented against any of those categories is inherited by Cephalexin, and (3) each ingredient keeps its own severity, likelihood, and evidence grades from the underlying record. That’s why one supplement can carry several records for one drug — it may interact through more than one category.

Cephalexin sits in 7 interaction categories. Open any one to see what the group means:

Antibiotic Drugs 27 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

27 of the supplement ingredients on this page reach Cephalexin through this category.

Oral Drugs 17 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

17 of the supplement ingredients on this page reach Cephalexin through this category.

Nephrotoxic Drugs 6 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

6 of the supplement ingredients on this page reach Cephalexin through this category.

Seizure Threshold Lowering Drugs 6 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

6 of the supplement ingredients on this page reach Cephalexin through this category.

Organic Anion Transporter 1 (Oat1) Substrates 4 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

4 of the supplement ingredients on this page reach Cephalexin through this category.

Organic Anion Transporter 3 (Oat3) Substrates 4 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

4 of the supplement ingredients on this page reach Cephalexin through this category.

Cephalexin (Keflex) 1 ingredient

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

1 of the supplement ingredient on this page reaches Cephalexin through this category.

About Cephalexin

Cephalexin is a cephalosporin antibiotic used to treat bacterial infections of the respiratory tract, bones, skin, ears, and urinary tract.

Generic name: Cephalexin  ·  Brand names: Keflex, Keftab, Cephalex, Lexin.

See the full Cephalexin drug information

Related: does Cephalexin deplete any nutrients?

Cephalexin has 28 reported nutrient associations in the research literature — see the Cephalexin nutrient depletion report.

Check a real product

Take a Supplement Product? Check the Whole Bottle Against Cephalexin

Most supplements are combination products — and the interaction may come from an ingredient you didn’t buy it for. Search any product below (or scan its label) and we’ll check every ingredient on it against Cephalexin.

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Pharmacist Counseling Corner

Cephalexin & Supplements: Common Questions

What supplements interact with Cephalexin?
More than you might expect — 61 in total, though they are far from equal: 3 are rated major, 47 moderate, and 11 minor. The ranked list on this page puts the ones that genuinely matter first, and every entry opens a full report on that exact pair. The highest-ranked right now: Siberian Cocklebur, Activated Charcoal, Asarabacca.
Which Cephalexin supplement interactions are the most serious?
Focus on the major group: Siberian Cocklebur, Activated Charcoal and Asarabacca. A major rating means the combination can be clinically significant, not that harm is guaranteed — but it's exactly the kind of thing to run past your pharmacist before your next dose, not after. Jump to the ranked list.
Can I take vitamins or supplements while on Cephalexin?
Usually yes — most people on Cephalexin can take most supplements. The catch is the exceptions, and they aren't always the exotic ones (St. John's Wort trips up more prescriptions than almost anything sold next to it). Look up each ingredient you actually take in the list above, and treat "no known interaction" as a green-ish light, not a guarantee. Try the label scanner or the interaction checker.
Do brands like Keflex have the same supplement interactions as Cephalexin?
Yes — Keflex, Keftab, Cephalex, Lexin all contain Cephalexin, so everything on this page applies to them equally. Interactions belong to the active drug, never to the brand on the box; the same is true of generics.
Where do these interaction ratings come from?
Every rating comes from the Natural Medicines database — the same evidence-graded reference pharmacists and hospitals use — and each interaction carries three separate grades: severity (how bad it can be), likelihood (how well it's documented in studies and case reports), and an evidence level. Our pharmacists review the content; we never let an AI decide an interaction. See how to read the ratings and our editorial policy.
Does Cephalexin deplete any vitamins or nutrients?
It might — Cephalexin has 28 reported nutrient-depletion associations in the research literature, which is a different question from interactions: instead of a supplement changing the drug, the drug may lower a nutrient over time. See the Cephalexin nutrient depletion report for the specifics and what to discuss with your pharmacist.
What about Cephalexin and my other medications?
This page covers Cephalexin against supplements and herbal ingredients. Checking Cephalexin against your other prescription or OTC medications is a different tool — our drug interaction checker covers that side. Head to the drug–drug interaction checker, or read the full Cephalexin drug information.

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

Where next

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Sourcing

Where This Data Comes From — and Why You Can Trust It

🧪 Licensed clinical database

Every interaction verdict on this page comes from Natural Medicines Pro (TRC Healthcare / Therapeutic Research) — the same evidence-graded reference used by pharmacists and hospitals. We license this data directly; we do not scrape it, and no AI invents an interaction.

🧑‍⚕️ Pharmacist review

This page is curated and coded by , Clinical Pharmacist, with additional analysis by the HelloPharmacist Pharmacist Team. Editorial commentary is ours; the licensed interaction records are shown as sourced.

🔄 Kept current

Our interaction database refreshes on a weekly cycle, and this page re-checks the live database every time it’s rebuilt — what you see reflects the database as of September 22, 2026.

🔍 Full transparency

How every dataset on this site is sourced, licensed, and updated is documented publicly: our data sources · editorial policy · how we use AI.

Educational information, not medical advice. An interaction being on file does not mean it will happen to you — and absence of one is not proof of safety. Never start or stop a medication or supplement without talking to your pharmacist or doctor.