Spanish police were called to meet an aeroplane carrying singer Pete Doherty at Barcelona Airport after EasyJet said crew members found a syringe on board.
Pete Doherty is in Barcelona for the Primavera Sound Festival
An EasyJet spokeswoman said crew found "a syringe hidden in a bin, covered in blood" in the plane's toilet.
Spanish Guardia Civil met Doherty and four friends but found no suspicious substances in the lavatories.
They were not arrested. Doherty's band Babyshambles played at the Primavera Sound Festival in the city on Thursday.
The EasyJet spokeswoman said the crew became suspicious after Doherty spent "an unusual amount of time in the toilet".
'Agitated and aggressive'
After the discovery of the syringe, Doherty was questioned by crew and became "agitated and aggressive", the spokeswoman said.
The captain contacted Spanish police, who met the plane, which was held on the ground for about half an hour.
Officers only found a bottle of heroin substitute methadone, which Doherty is taking as part of a drug treatment programme.
Aviation regulations mean passengers must inform an airline in advance if they are carrying a syringe for medical reasons and Doherty failed to do so, EasyJet said.
"You simply cannot take syringes on an aircraft without permission and cause a potential hazard to other passengers," the spokeswoman said.
The singer and his bandmates were travelling on flight EZY5135 from London Gatwick.
The band have now been banned from travelling on EasyJet flights in the future, the spokeswoman added.
At the start of Babyshambles' performance at the Primavera Sound Festival, Doherty made a remark attacking EasyJet.