It passed, but over the next few days he experienced more thunderclap headaches — that’s the clinical term — so he sought medical attention.

Scans of his head and neck showed the kind of constriction in some arteries that can cause intense headaches, doctors reported on Monday in BMJ Case Reports. The scientific term for this temporary narrowing of arteries is reversible cerebral vasoconstriction syndrome.

Dr. Kulothungan Gunasekaran, one of the report’s authors, now at the Henry Ford Hospital in Detroit, said that for some reason the man must have been particularly sensitive to capsaicin. The Carolina Reaper is a popular pepper, and many people eat them and experience nothing worse than the desire to cut out their own tongues.

“I was discussing the case with a nurse who had eaten three Carolina Reapers,” Dr. Gunasekaran recalled.

The Reaper has been measured at more than two million Scoville heat units, the accepted scale for how hot peppers are. Measurements vary, but a really hot habanero might come in at 500,000 Scoville units.

The patient was fine, with no lingering damage, but thunderclap headaches are not to be dismissed. For one thing, there’s the pain, which seems to surpass even the normal effect of the peppers.