Sniffer dogs should be used to look for drugs in all UK schools, say experts.
A team studied the results of a trial at six schools in Buckinghamshire and found the searches are good at stopping pupils bringing drugs into school.
During the trial two specially trained dogs went into schools to search for drugs on the premises and on pupils.
Experts recommended that searches for drugs should be random to stop pupils bunking off to avoid being caught, or warning each other on mobile phones.
During the trial a spaniel was used to search buildings and classrooms.
At the same time a labrador was positioned outside the school gates to check whether pupils were carrying drugs, or had come into contact with them.
Sniffer dog support
Most pupils (82%), parents (98%) and staff (92%) involved in the trial were in favour of using the sniffer dogs.
Emily, 14 told Newsround: "The dog went into lessons and we thought it was a good deterrent. I'm not nervous about the checks now."
Last year sniffer dogs started carrying out random checks on school buses in South Yorkshire.
And pupils at the Abbey School in Faversham, Kent, have been having random drugs tests since January.