Ergotism: The Fungal Infection That People Claim Caused the Salem Witch Trials

I want to be upfront with you on this one: the title contains the word “probably” for a reason. The ergot theory is one of the most widely repeated explanations for the Salem witch trials, and it is also one of the most contested. Historians who specialize in Salem have serious objections to it. I am going to give you the full picture because the full picture is actually more interesting than the clean version. But first, the fungus.

What Ergot Actually Is

Ergot is a fungus called Claviceps purpurea that grows on rye and other grains under wet, cool conditions. It produces a cluster of dark, grain-shaped growths that replace the normal kernels on an infected plant. Until the 1800s, farmers could not reliably distinguish ergot from the grain itself. It went through the mill with everything else, into the flour, and into the bread.

Eating ergot-contaminated bread causes ergotism, and ergotism comes in two forms. Gangrenous ergotism causes the blood vessels to constrict so severely that tissue dies. Limbs turn black and fall off. Medieval Europeans called it St. Anthony’s Fire because of the burning sensation and because the Order of St. Anthony specifically ran hospitals to treat its victims. Records of mass ergotism outbreaks appear throughout European history. One episode in France in 944 AD killed tens of thousands of people. Another swept through the Rhine Valley in 1039. The disease recurred so reliably that entire communities learned to associate its onset with divine punishment.

Convulsive ergotism is the other form, and it is the one relevant to Salem. Its symptoms include hallucinations, violent muscle spasms, convulsions, crawling sensations under the skin, a sensation of being bitten or pinched by invisible forces, and a terrifying feeling that something unseen is attacking you. In a 17th-century Puritan community with no framework for understanding neurological poisoning, convulsive ergotism would look exactly like one thing: demonic possession.

Here is the key chemical detail: LSD is derived from ergot. The fungus produces lysergic acid, and ergotism is essentially an uncontrolled, agonizing psychedelic experience combined with extreme physical pain. The hallucinations are not metaphorical. They are pharmacologically real.

What Happened in Salem in 1692

In the winter of 1691 to 1692, a group of girls in Salem Village, Massachusetts began experiencing strange symptoms. Betty Parris, nine years old, and her cousin Abigail Williams, eleven, started having fits. They described visions, said they felt pinched and bitten by invisible creatures, and occasionally fell into convulsions. Other girls in the community developed similar symptoms. The local doctor, William Griggs, examined them and concluded that the cause was supernatural. The girls began accusing neighbors of sending spectral figures to torment them.

By the time the panic ended in the fall of 1692, courts had tried over 200 people. Nineteen died by hanging. One man, Giles Corey, was pressed to death with heavy stones when he refused to enter a plea. Several others died in prison awaiting trial. The girls’ accusations had effectively destroyed a community.

The question that historians have argued about ever since is what caused the initial symptoms. Mass hysteria is one explanation, and a well-supported one. Social and political tensions within Salem Village are another. But in 1976, a different explanation arrived that briefly felt like it resolved everything.

The Ergot Theory and Why It Spread

Linnda Caporael was a psychology graduate student at the University of California, Santa Barbara when she published a paper in Science magazine proposing that ergot poisoning explained the Salem witch trials. Her paper was titled “Ergotism: The Satan Loosed in Salem?”

Her argument was detailed and genuinely compelling. The summer of 1691 had been wet and warm, ideal conditions for ergot growth on rye. Salem Village’s primary grain crop was rye. The afflicted girls described hallucinations, convulsions, sensations of being bitten and pinched by invisible forces, and visions of spectral figures. These symptoms matched convulsive ergotism so closely that Caporael argued the connection was not coincidental.

Furthermore, she noticed a striking geographic pattern in the accusations. Most of the accusers came from the western side of Salem Village. Most of the accused lived to the east. The two areas drew from different grain supplies and different farming households. If contamination affected the western grain supply specifically, the pattern of who experienced symptoms and who did not would follow exactly the geographic map Caporael was looking at. That kind of spatial correlation is not easy to dismiss.

The theory spread remarkably fast for academic work. It appeared in textbooks, documentary films, and popular history books within years of publication. Today it remains the first explanation most people encounter when they read about Salem, which is a testament to how satisfying it is as an answer.

The Problems With the Theory

Almost immediately after Caporael published, two researchers named Nicholas Spanos and Jack Gottlieb responded with a direct rebuttal in the same journal. Their objections were substantive, and most Salem historians have sided with them in the decades since.

The first major problem involves vitamin A. Communities historically affected by convulsive ergotism share one consistent feature: severe vitamin A deficiency. Vitamin A, found in dairy products and fish, apparently plays a significant protective role against the worst effects of ergot poisoning. Salem Village was not a vitamin A-deficient community. It had cattle, dairy production, and ready access to coastal fish from nearby ports. The population that got sick should, by historical precedent, have had significant protection against convulsive ergotism even if the grain had been contaminated.

The second problem is how the symptoms spread. Ergotism is a dietary poisoning. It affects households collectively, because households share food. Multiple family members eating the same contaminated bread get sick at the same time. In Salem, the afflictions moved person to person in patterns inconsistent with dietary poisoning. Symptoms appeared selectively within households. They also appeared and disappeared inconsistently, sometimes flaring dramatically during court proceedings and subsiding afterward, which is not behavior that a fungal neurotoxin produces on a social schedule.

The third problem is that the geographic pattern Caporael identified does not hold up as cleanly under scrutiny as her paper suggested. Later researchers examining the same records found that the accused and accuser distribution across the village was more complicated than a simple east-west split, and that the pattern could be explained by pre-existing family and land disputes without requiring a contaminated grain supply.

Why the Theory Persists Anyway

Here is the genuinely interesting part, and the reason I think this topic is worth writing about even if the specific theory is probably wrong. The ergot theory persists because it is the most morally comfortable explanation available.

Every other serious explanation for Salem requires sitting with genuine human ugliness. Land disputes between families with generations of bad blood. The specific dynamics of young women in a society that offered them essentially no power, who discovered that accusations gave them an extraordinary and terrifying form of influence. A legal framework that made accusation nearly equivalent to conviction. A theological environment so saturated with the reality of the devil that spectral evidence felt as legitimate as physical evidence. Community cruelty, collective moral failure, and the specific mechanisms by which ordinary people participate in extraordinary injustice.

Those explanations are probably closer to the truth. However, they do not resolve anything cleanly. They just describe a community that destroyed itself through recognizable human mechanisms, which means they force us to think about how communities do that and whether ours are different.

The ergot theory offers something different and considerably more comforting. It says the girls genuinely experienced something. Nobody was calculating. Nobody chose cruelty. A fungus poisoned the bread, the community responded to what it witnessed with the only framework available, and tragedy followed from a biological accident rather than from human nature doing what human nature sometimes does.