Drug & supplement interaction

Ergot + 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 Ergot 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.

Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Ergot 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 Ergot 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.

Ergot safety at a glance

Ergot overall Avoid Crude ergot is toxic and can cause serious, even fatal, poisoning; it should not be used as a supplement.
Pregnancy Unsafe When used orally due to risk for toxicity and stillbirth; avoid using. Read the full pregnancy detail
Breastfeeding Unsafe When used orally due to risk for toxicity and stillbirth; avoid using. Read the full breastfeeding detail

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 Ergot? 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. Ergot has documented interactions with 4 drug classes — the most serious being cytochrome p450 3a4 (cyp3a4) inhibitors (moderate), ergot derivatives (moderate) and serotonergic 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

Ergot Does Interact With Other Medications

Ergot has 462 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 462 No known interaction 2,368 (incl. Cephalexin)
Taking anything else?

Check Another of Your Medications Against Ergot

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

What to actually watch for

No Interaction Found — But Data Suggests Ergot 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. 2 of them are worth acting on rather than waiting out — marked below.

  • Confusion Worth acting on Additional detail

    Ergot

    “Orally, ergot can cause gastrointestinal symptoms such as nausea and abdominal pain. Weakness, muscle pain of the extremities, and numbness and tingling of the fingers and toes may also occur (9). Symptoms of acute overdose include nausea, vomiting, diarrhea, extreme thirst, coldness, tingling and itching of the skin, a rapid and weak pulse, hypotension, shock, confusion, seizures, unconsciousness, and death (9).

    Chr…”

    Ergot · Natural Medicines adverse-effect record, reported in diarrhea.

    3 sources cited
    1. 9. Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
    2. 11163. Eadie MJ. Convulsive ergotism: epidemics of the serotonin syndrome? Lancet Neurol 2003;2:429-34. PubMed
    3. 11164. Etzel RA. Mycotoxins. JAMA 2002;287:425-7.

    “Orally, ergot can cause drowsiness, delirium, lethargy, mental changes, and visual disturbances (9,11163).”

    Ergot · Natural Medicines adverse-effect record, reported in delirium.

    2 sources cited
    1. 9. Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
    2. 11163. Eadie MJ. Convulsive ergotism: epidemics of the serotonin syndrome? Lancet Neurol 2003;2:429-34. 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

    Ergot

    “Symptoms of acute ergot oral overdose include nausea, vomiting, diarrhea, extreme thirst, coldness, tingling and itching of the skin, a rapid and weak pulse, hypotension, shock, confusion, seizures, unconsciousness, and death (9).”

    Ergot · Natural Medicines adverse-effect record, reported in diarrhea.

    1 source cited
    1. 9. Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.

    Cephalexin

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

  • Fever Additional detail

    Ergot

    “Orally, chronic toxicity from cumulative ergot doses over a short period of time can present as a convulsive form of ergotism. Symptoms include muscle spasms in the trunk and limbs, painful involuntary flexion of the fingers and wrists, and either flexion or extension of the ankles. Sweating, fever, muscle stiffness, twitching and seizures have also been reported (9,11163).”

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

    2 sources cited
    1. 9. Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
    2. 11163. Eadie MJ. Convulsive ergotism: epidemics of the serotonin syndrome? Lancet Neurol 2003;2:429-34. PubMed

    Cephalexin

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

  • Itching Additional detail

    Ergot

    Recorded for Ergot in the same Natural Medicines adverse-effect record shown under Confusion above.

    Cephalexin

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

  • Stomach pain / Diarrhea / Vomiting / Nausea Additional detail

    Ergot

    “Orally, ergot can cause gastrointestinal symptoms such as nausea, vomiting, diarrhea, and abdominal pain (9).”

    Ergot · Natural Medicines adverse-effect record, reported in diarrhea.

    1 source cited
    1. 9. Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.

    Cephalexin

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

  • Tiredness Additional detail

    Ergot

    Recorded for Ergot in the same Natural Medicines adverse-effect record shown under Confusion above.

    Cephalexin

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

Reported for Ergot but not commonly for Cephalexin: blurred vision, joint or muscle stiffness, muscle pain and low blood pressure.

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

Ergot in Pregnancy & Breastfeeding

Pregnancy And Lactation Unsafe

When used orally due to risk for toxicity and stillbirth; avoid using.

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 Ergot 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 Ergot 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 Ergot 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 Ergot 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 Ergot
Steady interest

#1,016 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 Ergot reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Ergot 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 Ergot

What is Ergot?

Ergot
  • Heavy menstrual or uterine bleeding
  • Bleeding after childbirth
  • Migraine headaches
  • Stimulating uterine contractions

Ergot is a toxic fungus that grows on rye and contains powerful chemicals (ergot alkaloids) that strongly narrow blood vessels and squeeze the uterus. Because raw ergot is poisonous and the dose is impossible to control safely, it should never be used as a home remedy or supplement. Some purified ergot chemicals are used as prescription drugs under strict medical supervision, but the crude herb is not safe to take.

Claviceps purpurea · Clavicipitaceae · The fungal mass (sclerotium) that grows on rye and other grasses · Historically used as crude dried fungus; purified ergot alkaloids are available only as prescription medicines (not as a dietary supplement)

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

Ergot: dosing

There is no safe established dose of crude ergot for self-care, and it should not be taken as a supplement. The amount of active chemical in the raw fungus varies and cannot be measured reliably at home, which makes poisoning very easy.The only safe way ergot chemicals are used is as purified, carefully measured prescription medicines given and monitored by a healthcare professional. Do not try to make or take any ergot preparation on your own.

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

Read the full Ergot 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 & Ergot

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

0Major
462Moderate
0Minor
2,367No known interaction
462 Moderate 2,367 No interaction
Moderate

462 interactions

Showing 60 of 462 moderate interactions — see all 462 on the Ergot page.

No interaction 2,367 drugs checked — show the list

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

Showing the 60 most looked-up of 2,367 medications checked with no known interaction — see the full Ergot list.

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

Ergot References

The 4 references that drive our Ergot 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. Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
  2. Singhal AB, Caviness VS, Begleiter AF, et al. Cerebral vasoconstriction and stroke after use of serotonergic drugs. Neurology 2002;58:130-3. PubMed
  3. Eadie MJ. Convulsive ergotism: epidemics of the serotonin syndrome? Lancet Neurol 2003;2:429-34. PubMed
  4. Etzel RA. Mycotoxins. JAMA 2002;287:425-7.

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 Ergot and Cephalexin Together: Common Questions

Is it safe to take Ergot with Cephalexin?
We do not list a known interaction between Ergot 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 Ergot and Cephalexin have any of the same side effects?
Yes — our sources link each of them separately to 9 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 Ergot and Cephalexin combination checked?
Interactions in our licensed database are recorded against drug classes. Cephalexin is filed under 7 classifications, and Ergot has documented interactions with 4 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 Ergot interact with any other medications?
Yes. Ergot has 462 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 — Ergot 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

Ergot 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 4 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Cephalexin and Ergot?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.