Schoolchildren in Ohio were left needing treatment after eating the bhut jolokia chillies – one of the most powerful chilli peppers known to exist.

Emergency services were called after students suffered allergic reactions and started displaying symptoms including "blotchy skin, hives, tearing of eyes, sweating and general discomfort".

"This was serious but sometimes situations at schools become far more serious than this," said Superintendent Brad Ritchey of Milton-Union Exempted Village Schools.

Of the worst-affected pupils, five were taken to hospital and 40 were given treatment.

"We all drank like 10 cartons of milk," Cody Schmidt, an eighth-grade student told the Dayton Daily News. "It was really hot."

The incident happened at lunchtime and a subsequent investigation revealed that the children had all eaten the peppers voluntarily.

One 13-year-old boy broke out in a rash and had trouble seeing, while two other students vomited according to reports.

Superintendent Ritchey said the pupil who brought the peppers to school has been identified but they have not decided whether or not to bring any disciplinary action.

"It was definitely a disruption, and school disruptions are in our school code of conduct," Ritchey said.

The bhut jolokia was the world's hottest chilli in 2007 with a Scoville rating of around 1 million. It has since been displaced by the Carolina Reaper, which has a Scoville rating of 1.57 million. Jalepono and Scotch Bonnet chillis have Scoville ratings of 100,000.

Recently, India authorised the use of grenades that disperse a gas made from ghost chillis as crowd-control measures in Kashmir.