Police used the force's new drugs itemiser - which scans people for traces of banned substances - at the Litten Tree pub. It was the first time the new technology, which detects traces of drugs from heroin to cannabis, had been used in the town.
Police officers tested 150 revellers as they arrived at the pub in Sheep Street between 10.30pm and midnight on Friday.
The pub managers barred anyone refusing to co-operate with the test from entering.
Det Sgt Steve Duffy, of Banbury CID, said two people tested positive and were searched but not found to be in possession of drugs. The pair were then banned from entering the pub, but not arrested.
Mr Duffy said: "It went very well. We gained the full co-operation of the management and the customers." He said: "The public were very supportive. Many people were saying they wanted to be tested."
Drug Scanner Checks Public