A teaching union has branded caffeine and energy drinks as "legal highs" and warned about their negative impact on pupils' behaviour in schools.
The NASUWT teaching union is working with drug and alcohol charity Swanswell to examine the consumption of drinks such as Red Bull, Monster and Relentless.
Teachers have reported increasing concerns about the effect on behaviour, concentration and energy levels as a result of the drinks, which contain high levels of caffeine and sugar.
Some 13% of teachers who responded to a survey by the NASUWT cited caffeine and energy drinks as a cause of poor pupil behaviour.
Chris Keates, the union's general secretary, said: " This is the first time we have seen a significant number of teachers beginning to raise this as a concern.
"These drinks are becoming increasingly popular among young people and are often seen as simply like any other soft drink, but many young people and their parents are not aware of the very high levels of stimulants that these drinks contain.
"They are readily available legal highs.
"Teachers are growing increasingly concerned that some young people are using these drinks to enable them to stay up into the early hours of the morning and then replace their lost energy by drinking two or three cans of these drinks on their way to school.
"Teachers are reporting that this affects concentration in class and hyperactivity is then followed by the inevitable crash later in the school day when the impact of these drinks wears off.
"Parents and young people need to be made aware of what these drinks contain and their potential impact on behaviour."
According to Swanswell it is "logical" that children should consume a maximum of 200mg of caffeine per day, which is the same limit recommended by the Food Standards Agency for pregnant women.
Figures released by the charity show that 500ml cans and bottles of popular energy drinks contain 144-160mg of caffeine. This means that children can only drink one energy drink to reach the daily caffeine intake limit, compared with five 500ml bottles of cola which contain 39.6mg of caffeine.
Debbie Bannigan, chief executive of Swanswell, said: " As a provider of drug and alcohol services for young people we're concerned about excessive energy drink consumption, not least because we're finding links to use of other substances, including alcohol, cannabis and Mephedrone."
Gavin Partington, d irector general of the British Soft Drinks Association (BSDA), said: " BSDA supports the School Food Trust's rules on what drinks can be sold in schools but of course it is for teachers to decide what pupils are allowed to take into school.
"It's worth remembering that coffees from popular high street chains contain the same or more caffeine than most energy drinks. However, like all food and drink, energy drinks should be consumed in moderation and as part of a balanced diet.
"Since 2010 the British Soft Drinks Association has operated a code of practice which says that high caffeine content soft drinks are not recommended for children, and specifies that this information should be clearly stated on the label of such drinks.
"The BSDA code of practice also states that high caffeine content drinks should not be promoted or marketed to those under 16."