Each can contains the same amount of caffeine as a cup of coffee
A school has banned the high-energy drink Red Bull after staff reported an increase in bad behaviour.
Chatsmore Catholic High School in Worthing, West Sussex, said some children's conduct changed after consuming the drink.
Acting head Anne Ward said the drink, which contains 80mg of caffeine per can, had been banned from the grounds.
Red Bull said it did not recommend the drink to caffeine-sensitive individuals, including children.
The Tesco-branded Kick high energy drink has also been banned from the 630-pupil school, in a bid to stop the escalation in bad behaviour.
'Issue for parents'
"We found that a small number of children's behaviour was less appropriate after they had been drinking these drinks," said Ms Ward.
"We were becoming increasingly concerned about the level of inappropriate behaviour so decided to take action before it becomes a bigger issue.
"If they want to drink these drinks outside school then that is an issue for their parents.
"We advocate drinking water and indeed we allow pupils to drink water during lessons."
Each can of Red Bull, which has the slogan "Red Bull gives you wings", contains about the same amount of caffeine as a cup of coffee.
Makers say it can improve performance and boost concentration.
Red Bull said the drink was suitable for people at the same age as coffee or other caffeinated beverages.
"People have different sensitivity to caffeine [and] the daily consumption of Red Bull Energy Drink should conform to a person's intake of caffeine," it said in a statement.
"However, in general children are more sensitive to caffeine than adults.
"This is why we do not recommend Red Bull Energy Drink to caffeine-sensitive individuals including children."