Essendon says it has asked the AFL to investigate possible inappropriate use of supplements among its playing group in the 2012 pre-season.
The AFL club has also contacted the Australian Sports Anti-Doping Authority (ASADA) and requested their assistance in the investigation.
Club chairman David Evans, chief executive Ian Robson and coach James Hird held a media conference on Tuesday afternoon after meeting with the AFL to inform it of the discovery.
“In the last 48 hours we’ve received information about supplements that have been given to our players as part of fitness program in 2012,” Evans said.
“Given the information we received and the questions it has raised ... we consulted with our staff and briefed our board and all of our players today.
“Secondly we contacted the AFL and met with Gillon McLachlan and Brett Clothier to brief them and seek their advice.
“Following that discussion we requested that the AFL commence an immediate investigation.”
Evans said ASADA agreed to launch an investigation immediately.
He said the club was seeking a “clean bill of health”.