It just wouldn’t be Christmas without nutmeg. The tasty spice found in virtually every kitchen adds just the right zing to pumpkin pie, eggnog, mulled cider, wassail, and countless other holiday dishes. Unbeknownst to most, it is also a powerful hallucinogenic drug and powerful toxin.

Most recipes that call for nutmeg invite the cook to add a pinch or two of the spice, or perhaps as much as half a teaspoon to a dish that will be divided among many people. If one person takes much more than that, really bad things can happen. As little as 5 to 15 grams (1 to 3 teaspoons) of the spice is a toxic dose. The dosage acts as an anticholinergic, inhibiting the brain’s ability to process the neurotransmitter acetylcholine. The symptoms of toxicity include hallucinations, palpitations, and feelings of impending doom. Some report an out-of-body sensation, but the most common symptoms include intense nausea, dizziness, extreme dry mouth, and a lingering slowdown of normal brain function. Most symptoms pass within 24 hours, however, there are reported cases where nutmeg-associated psychosis lasts for up to six months.

The 1992 article “Acute nutmeg intoxication” in the American Journal of Emergency Medicine describes the symptoms of nutmeg poisoning, focusing on the case of a 23-year-old college student who overdosed on the spice. That student is not the first to experience the effects. In the Middle Ages, it was used to end unwanted pregnancies. Since that time, there have been cyclical episodes of nutmeg abuse through ingesting or smoking. In recent years, it has taken on a new life in the prison system where inmates grasp at the opportunity for an accessible drug alternative. In his book, The Autobiography of Malcolm X, the activist recounts his own use of the spice while he was incarcerated. “A penny matchbox full of nutmeg had the kick of three or four reefers,” he wrote. A few years ago, a man in Sweden claimed that nutmeg had induced him to spit at strangers on the street.

The researchers uncovered 32 cases in a 10-year period; 17 were accidental and 15 were deliberate. Of the deliberate cases, most involved young people between the ages of 15 and 20 who were mixing nutmeg with pharmaceuticals. Of that group, one had such a bad reaction that he ended up on a ventilator. Another study in California, tracking 119 incidents involving nutmeg from 1997 to 2008, reached a similar conclusion, although the authors found a higher level of deliberate abuse. In that case, 72.3 percent of the poisoning cases involved intentional use.

“It’s not that nutmeg cases are that common,” said Leon Gussow, an Illinois toxicologist who publishes a blog for professionals called The Poison Review. “But toxicologists do recognize it as one of the more interesting spices in the kitchen.”

Nutmeg is the seed of an evergreen tree, Myristica fragrans. The spice mace comes from a thin protective layer that encloses that seed. It was introduced to Europe 900 years ago. It quickly earned a reputation for being able to do much more than make food tastier. It was used as an anti-infection medication, as well as a repellant to the Black Plague.

“People have told me that it feels like you are encased in mud,” said Dr. Edward Boyer, professor of emergency medicine and chief of the division of medical toxicology at the University of Massachusetts Medical School. “You’re not exactly comatose, but you feel really sluggish. And your remembrance of events during this time period is incomplete at best.”

The usual holiday samplings of nutmeg is not a risk, so if you are accustomed to enjoying a little bit of the spice with your holiday menu, keep it up. Be aware of the dangers, however, of leaving the nutmeg jar out where it can be reached by young children. Those who are considering testing the hallucinogenic effects of the spice would do well to read the symptoms that come from experimenting with higher doses: feelings of impending doom, nausea, and other nasty side-effects should be enough to tell you that you would be better off enjoying nutmeg in the manner it was intended.

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