Herb & supplement monograph

Ergot Drug Interactions, Uses, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Ergot interacts with medications. The heart of this page is the interaction list — every drug Ergot is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Ergot is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Ergot Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, Ergot drug interactions are rated moderate across the board, but almost all of them rest on theoretical concerns rather than proven harm in people. None of the listed interactions are rated major, yet none are minor either, and every one is graded as only possible, meaning the evidence comes from lab research or limited reports rather than solid human studies.

Interactions deserving the most attention

The combinations we would watch most closely involve CYP3A4 inhibitors, such as clarithromycin, ritonavir, and diltiazem, because these drugs may slow how the body clears ergot compounds and could raise the risk of ergot toxicity. Taking ergot alongside ergot-derivative medicines like ergotamine or dihydroergotamine may stack similar effects and side effects. There is also a theoretical concern that ergot combined with serotonergic drugs could add to serotonin-related side effects, and stimulants may add to blood-vessel narrowing.

What the rest of the list means

The long list of interacting medications comes from a handful of broad drug categories, not hundreds of individually proven problems. Most concerns are predictions based on how ergot compounds might affect an enzyme the body uses to clear certain medications, or how their effects might overlap, and these predictions have not been confirmed in well-controlled human studies.

Check your medications against Ergot

Based on HelloPharmacist’s Ergot interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Ergot

462 medications have a known interaction with Ergot, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Ergot using our pharmacist-reviewed interaction data.

AI summaries are generated from our Ergot interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

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 drug listed above links to the full report for that exact Ergot combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Ergot affects

Every type of medication (drug category) Ergot is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 4 drug categories Ergot interacts with

Cytochrome P450 3a4 (cyp3a4) InhibitorsErgot DerivativesSerotonergic DrugsStimulant Drugs

Cytochrome P450 3A4 (Cyp3A4) Inhibitors

Ergotamine, a constituent of ergot, is a substrate of cytochrome P450 3A4 (CYP3A4). Theoretically, drugs that inhibit CYP3A4 might increase the risk of ergot toxicity. Some of these drugs include amiodarone (Cordarone), clarithromycin (Biaxin), diltiazem (Cardizem), erythromycin (E-mycin, Erythrocin), indinavir (Crixivan), ritonavir (Norvir), saquinavir (Fortovase, Invirase), and many others.

Likelihood Possible Evidence D

Ergot Derivatives

Concomitant use of ergot with ergot alkaloids or derivatives may increase the risk of adverse effects. Some of these include bromocriptine (Parlodel), dihydroergotamine (Migranal, DHE-45), ergotamine (Cafergot), and pergolide (Permax).

Likelihood Possible Evidence D

Serotonergic Drugs

Certain ergot alkaloids, such as dihydroergotamine, act as serotonin agonists. Theoretically, combining serotonergic drugs with ergot might increase the risk of serotonergic side effects including serotonin syndrome and cerebral vasoconstrictive disorders. Monitor patients for signs of serotonin syndrome and other serotonergic side effects if using ergot with serotonergic drugs.
Serotonergic drugs include the selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine (Prozac), paroxetine (Paxil), and sertraline (Zoloft); tricyclic and atypical antidepressants such as amitriptyline (Elavil), clomipramine (Anafranil), and imipramine (Tofranil); triptans such as sumatriptan (Imitrex), zolmitriptan (Zomig), and rizatriptan (Maxalt); opioids such as methadone (Dolophine) and tramadol (Ultram); and many other medications.

Likelihood Possible Evidence D

Stimulant Drugs

Co-administration of stimulant drugs with ergot may increase the risk of vasoconstriction.
Some stimulant drugs include albuterol (Proventil, Ventolin), diethylpropion (Tenuate), dopamine, epinephrine, phentermine (Ionamin), pseudoephedrine (Sudafed), and many others.

Likelihood Possible Evidence D

Monograph

Ergot: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

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.

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

People commonly use it for

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

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallBest avoided

Crude ergot is toxic and can cause serious, even fatal, poisoning; it should not be used as a supplement.

PregnancyUnsafe

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

Read the full pregnancy detail

BreastfeedingUnsafe

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

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Overview

Ergot is not a plant or an herb in the usual sense. It is a fungus called Claviceps purpurea that infects rye and some other cereal grains and grasses. When it grows, it forms a hard, dark, curved body (called a sclerotium) in place of a normal grain. This is sometimes called "spurred rye" or "cockspur rye."

Ergot has a long and dangerous history. In the Middle Ages, people who ate bread made from rye contaminated with ergot developed a serious illness known as St. Anthony's Fire, or ergotism. This could cause burning pain, gangrene (loss of fingers, toes, or limbs from lack of blood flow), seizures, and hallucinations.

Despite its dangers, ergot has been used in traditional and early medicine to slow heavy bleeding and to help start or strengthen labor, because its chemicals strongly squeeze blood vessels and the uterus. Today, certain purified ergot chemicals are made into carefully measured prescription drugs, but the crude fungus itself is not a safe supplement.

Uses & effectiveness

People have traditionally used ergot for conditions linked to bleeding and the uterus, such as heavy menstrual bleeding and bleeding after childbirth. It has also been used in connection with migraine headaches, because it narrows blood vessels.

It is important to understand that any real medical benefit comes from specific, purified ergot chemicals used as prescription medicines under a doctor's care — not from taking the raw fungus. The crude herb cannot be dosed safely, and the amount of active chemical can vary widely and unpredictably.

As a self-care supplement, there is no reliable evidence that taking ergot is safe or effective, and the risk of poisoning is high. For these reasons, ergot is not recommended for home or supplement use.

How it works

Ergot contains a group of natural chemicals called ergot alkaloids (ergolines), such as ergotamine and ergometrine. These chemicals act on several receptors in the body, including those for serotonin, dopamine, and adrenaline-type signals.

One of their main effects is to make blood vessels narrow (called vasoconstriction). They also cause the smooth muscle of the uterus to contract. These actions explain why ergot can slow bleeding and squeeze the uterus, and also why it can be so dangerous — strong, uncontrolled vessel narrowing can cut off blood flow to fingers, toes, and other tissues.

Some ergot chemicals are also chemically related to compounds that affect the brain and can cause hallucinations. Much of what we know comes from the medical history of ergot poisoning and from studies of the purified prescription drugs rather than from the raw fungus.

Safety & precautions

Ergot is toxic and should not be used as a dietary supplement or home remedy. Even relatively small amounts of the crude fungus can cause poisoning (ergotism), and the strength of the active chemicals is unpredictable.

People with heart or blood vessel disease, high blood pressure, poor circulation, liver or kidney problems, or a history of stroke are at especially high risk and should never use it. Children and older adults are also at greater risk of harm.

Pregnancy: Avoid completely. Ergot can cause strong uterine contractions and reduce blood flow, which can endanger the pregnancy and the baby. Breastfeeding: Avoid. Ergot alkaloids can pass into breast milk, may harm the infant, and can reduce milk production. If you have a medical condition that you think ergot might help, talk to a doctor or pharmacist about safe, approved options instead.

Side effects

Ergot can cause a wide range of side effects, and many of them can be serious. Milder effects may include nausea, vomiting, diarrhea, stomach pain, headache, dizziness, and tingling or numbness in the hands and feet.

More serious effects come from strong blood vessel narrowing and can include cold, pale, or painful fingers and toes; muscle pain; high blood pressure; chest pain; and reduced blood flow that can lead to tissue damage or gangrene. High doses can cause confusion, hallucinations, seizures, and death.

Long-term or repeated exposure can also lead to chronic poisoning. Anyone who suspects ergot poisoning should seek emergency medical care right away.

Ergot: Reported Adverse Effects

Documented safety reports on Ergot from the evidence-graded Natural Medicines (TRC Healthcare) database, shown word-for-word from the licensed record.

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. 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.

Chronic toxicity, or ergotism, rarely occurs after a single oral dose. It usually results from cumulative doses over a short period of time. Ergotism from food is rare today. It is more common from overdoses of prescription ergot alkaloids. Symptoms of ergotism are related to circulatory disturbances. Numbness, coldness, and tingling of the extremities, particularly the feet and legs occur along with paleness or cyanosis. There may be no pulse in the affected area, which may develop into gangrene, especially in the toes. A convulsive form of ergotism may also occur. 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. Neurologic adverse effects such as drowsiness, delirium, lethargy, mental changes, and visual disturbances can also occur. Sweating, fever, muscle stiffness, twitching and seizures have also been reported.

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

Reports by condition

Delirium Neurologic/CNS

Orally, ergot can cause drowsiness, delirium, lethargy, mental changes, and visual disturbances.

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

Diarrhea Gastrointestinal

Orally, ergot can cause gastrointestinal symptoms such as nausea, vomiting, diarrhea, and abdominal pain.

Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.

Diarrhea Other

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.

Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.

Epilepsy Musculoskeletal

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.

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

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.

Adverse-effects data: Natural Medicines, Therapeutic Research Center

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. If you have a condition you think ergot might treat, speak with your pharmacist or doctor about proven, safer treatments.

Pregnancy & Breastfeeding

Ergot & Pregnancy

Unsafe

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

Eadie MJ. Convulsive ergotism: epidemics of the serotonin syndrome? Lancet Neurol 2003;2:429-34.
Etzel RA. Mycotoxins. JAMA 2002;287:425-7.

Ergot & Breastfeeding

Unsafe

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

Eadie MJ. Convulsive ergotism: epidemics of the serotonin syndrome? Lancet Neurol 2003;2:429-34.
Etzel RA. Mycotoxins. JAMA 2002;287:425-7.

Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center

References & further reading

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.

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

Keep reading

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.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

Pharmacist Counseling Corner

Ergot: Common Questions

Does Ergot interact with prescription medications?

Yes. We list 462 medications with a known interaction with Ergot. Use the checker above to see how Ergot interacts with a specific drug.

How are Ergot interactions rated?

Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.

Is it safe to take Ergot with my medications?

It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.

Where does this Ergot interaction information come from?

Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.

What is Ergot and where does it come from?

Ergot is a fungus (Claviceps purpurea) that grows on rye and other grains, forming a dark, hard body in place of the normal seed. It contains powerful chemicals called Ergot alkaloids that can affect blood vessels and the uterus.

Is Ergot safe to take as a supplement?

No. The raw fungus is toxic and can cause serious poisoning called Ergotism, including loss of blood flow to fingers and toes, seizures, and death. It should not be used as a home remedy or supplement.

Why was Ergot used in the past for childbirth and bleeding?

Ergot chemicals make blood vessels narrow and the uterus contract, which can slow bleeding and stimulate labor. Today these effects are achieved only with purified, carefully dosed prescription drugs given under medical supervision, not the raw fungus.

Can I take Ergot if I am pregnant or breastfeeding?

No. Ergot can cause strong uterine contractions and reduce blood flow, which is dangerous during pregnancy, and its chemicals can pass into breast milk and lower milk supply. Avoid it in both cases.

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

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Ergot Drug Interactions, Uses, Safety & More

Your Choice:

Ergot Drug Interactions: The Bottom Line

Drugs that interact with Ergot

Don’t want to scroll the list? Just ask.

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Likelihood — How Well It’s Documented

Where This Data Comes From

The kinds of drugs Ergot affects

Ergot: Uses, Safety & Side Effects

Overview

Uses & effectiveness

How it works

Safety & precautions

Side effects

Ergot: Reported Adverse Effects

Dosing

Ergot & Pregnancy

Ergot & Breastfeeding

References & further reading

Ergot: Common Questions

Related supplements & herbs

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