A hazardous materials response team was called to Cristo Rey Jesuit School in Baltimore, Maryland, after two students and three adults were taken to hospital with upset stomachs.
Several people also reported difficulty breathing.
Firefighters sourced the offending stench to a classroom on the third floor and, specifically, to a pumpkin spice plug-in air freshener.
Fire spokesman Roman Clark confirmed that five people had been taken to hospital for stomach ailments.
Panic over, classes resumed the next day.
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