Ergot is a type of fungus that can grow on grains such as rye and wheat. If a person eats the contaminated grains, it can result in ergot poisoning. The symptoms vary but can include dizziness, convulsions, psychosis, or gangrene.

In the past, midwives and doctors used ergot to induce childbirth. This was high risk and often caused harm to the parent or baby.

Today, doctors still use medications that contain ergot compounds to treat severe migraine and prevent bleeding after birth. These medications are far safer but still carry risks.

Some historians believe ergot poisoning played a role in several historical events, such as St. Anthony’s Fire and the Salem witch trials.

This article discusses the history, symptoms, and treatment of ergot poisoning. It also examines whether ergot is medicine.

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Ergot poisoning happens when a person or animal consumes Claviceps purpurea and its byproducts. This fungus grows on grains such as rye and wheat, producing toxic alkaloids. Other terms for ergot poisoning include ergotoxicosis or ergotism.

As C. purpurea grows, it replaces individual kernels of grain with dark, hard “ergots.” These ergots can mix into healthy grains during harvest, contaminating any products a person makes with the grain, such as bread or animal feed.

Ergot can affect the nervous system, digestive system, or cardiovascular system, constricting the blood vessels. This can lead to gangrene, which is when tissues die due to a lack of oxygen.

Some modern drugs contain compounds from ergot. While they are much safer than the historic use of ergot as medication, it is possible to get ergot poisoning from taking too many or taking them for too long.

Ergot poisoning still occurs today.

The mycologist Louis Rene Tulasne discovered the connection between rye and ergotism in the 19th century. Consequently, public health organizations increased their efforts to address ergot contamination, and larger outbreaks became rare.

However, outbreaks do still occur occasionally. They often happen in countries with lower economic development, but not always.

In recent decades, ergot poisonings have taken place in:

  • India in 1975
  • Ethiopia in 1977
  • Australia in 1987
  • the United States in 1996
  • Brazil in 1999

The use of modern medications that contain ergot-derived compounds can also result in poisoning.

Ergot poisoning may explain several notable historical events, including:

St. Anthony’s Fire

In the Middle Ages, people in Europe relied on rye as a staple food. However, this is one of the main grains that ergot can contaminate. After cold or wet winters or damp springs, the fungus could grow on rye from the previous harvest. By summer, the bread could be toxic.

As people did not know the cause of ergot poisoning, they named it St. Anthony’s Fire, after the order of monks who tried to treat those with the condition.

Dancing plague

From the 14–17th century, there were several outbreaks of the so-called “dancing plague” in parts of Europe. This caused people to uncontrollably dance or convulse for days at a time, sometimes resulting in injury or even death.

Experts are not sure what caused the dancing plague. Older research from 1997 suggests that several factors may have played a role, one of which may have been ergot poisoning.

Salem witch trials

In 1692, young girls in Salem, Massachusetts, became ill and began to exhibit unusual symptoms, including:

  • skin lesions
  • hallucinations
  • temporary blindness
  • convulsions

The local doctor diagnosed the cause of this illness as “bewitchment,” which led the town to start looking for potential witches within the community. They imprisoned 150 people from Salem and surrounding towns on suspicion of witchcraft, executing 14 women and five men in total.

One of the theories regarding the cause of the illness is ergotism.

Doctors sort ergot poisoning symptoms into three categories:

Neurological symptoms

These include:

Ergot poisoning that causes these symptoms is sometimes known as convulsive ergotism.

Gastrointestinal symptoms

These include:

Blood vessel symptoms

Ergot alkaloids can constrict the blood vessels for prolonged periods. The medical term for this is vasospasm. Vasospasm may occur in large arteries, such as those to the kidneys, neck, retina, and heart. However, 60–70% affect the legs and feet.

As vasospasm restricts blood and oxygen supply to affected parts of the body, it may cause:

  • coolness
  • paleness
  • muscle pain on activity progressing to muscle pain at rest

If tissues cannot get enough oxygen, they may die and become gangrenous. On rare occasions, people can also develop thrombosis, which is a blockage in a blood vessel from a blood clot.

Despite its toxicity, people have historically used ergot as medicine. People noticed that pregnant pigs that ate ergot went into premature labor, which led to midwives using ergots in humans. They would give whole ergots to people who had stalled labor, using a small dose for a restricted period of time.

The use of ergot during childbirth became more mainstream in the 1800s when doctors began to use it to speed up labor, even when there was no risk of complications. This resulted in an increase in stillbirths.

In the 20th century, scientists isolated specific ergot alkaloids and turned them into drugs. Today, doctors still use ergotamine and ergometrine, both of which are ergot alkaloids.

Ergotamine is a treatment for migraine. It stimulates the smooth muscle in the blood vessels to contract. This causes them to constrict, which decreases the dilation of arteries in the head.

Ergometrine is a drug that constricts blood vessels. Doctors use small and precise doses to prevent bleeding after birth, which is a major cause of death worldwide.

Researchers are investigating the use of ergot-based medications to treat Parkinson’s disease and dementia.

Ergot poisoning can present in several ways, so the process of diagnosing it may vary from case to case. For example, if a person taking ergot-based medication develops cold or pale legs and feet, a doctor may perform:

If an angiography shows an abrupt narrowing of arteries, it may indicate ergot poisoning. The treatment involves discontinuation of the drug, as well as caffeine and tobacco. These substances further constrict the blood vessels.

For some people, the problem resolves in 10 days. However, after prolonged use of an ergot-based drug, the disappearance of symptoms may take several months.

An additional treatment is antiplatelet therapy. Platelets are the fragments of the blood that promote normal clotting, so antiplatelet therapy prevents clotting and reduces the risk of clots.

If symptoms progress to pain at rest and gangrene, surgery may be necessary to remove dead tissue.

Below are answers to some common questions regarding ergot poisoning.

Can you get ergot poisoning from moldy bread?

Ergot poisoning is rare in the U.S. If a person buys bread and it becomes moldy at home, it is very unlikely to be C. purpurea.

That said, eating enough of any moldy bread can make someone sick. Some types of mold produce mycotoxins, which are harmful to the body.

The fuzzy patches a person can see on the surface of moldy bread is only part of the fungus. Its roots extend much deeper. If a person notices mold on bread, they should discard the entire piece or loaf.

Can ergot get you high?

Ergot fungus can produce hallucinations and psychosis, so it is a mind-altering substance. However, it is extremely dangerous to take it recreationally.

A related substance, lysergic acid diethylamide (LSD), is a semi-synthetic ergot alkaloid. It is not the same as ergot fungus but contains some similar compounds. LSD is the most potent known hallucinogen.

Can ergot cause abortions?

One of the historic uses for ergot was to induce labor and abortions. However, doing this was dangerous and required very precise doses.

Research from 2021 recounts an 1844 case where a doctor used ergot to conduct an abortion. It resulted in the death of the pregnant person.

Ergot poisoning occurs when a person ingests ergots, which are grains that contain the C. purpurea fungus. The fungus turns the grain hard and dark in color.

Symptoms of ergot poisoning can be neurological, gastrointestinal, or cardiovascular. Some historians believe it may partly explain some historical events, such as the Salem witch trials or the dancing plague.

Since the discovery of ergot and its toxicity, ergot poisoning has become uncommon. However, outbreaks can still happen. Ergot poisoning can also occur if a person takes ergot-based medication for a long time or takes too high a dose.