During the evening of Saturday 23 May 2015, Dorset Police was made aware that a number of people were taken to hospital after attending the Bournemouth 7s Festival.
It was reported that all had taken illegal substances. Their condition is not thought to be life-threatening.
Officers are investigating the circumstances.
Dorset Police and the organisers would like to warn people attending the festival not to take any illegal substances.
Anyone with information about anyone having offered such substances at the event should contact Dorset Police on 101
Witnesses and anyone with information should call Dorset Police in confidence on 101 quoting incident number 23:472. Alternatively, call the free and anonymous Crimestoppers line on 0800 555 111 where mobile phone tariffs may apply.