Premier League champions Chelsea were charged by the Football Association on Thursday with misconduct for allegedly breaching rules governing private drug testing by the club on some players last year.
Chelsea issued a statement saying the tests "directly relate to the Adrian Mutu case" and that the club would vigorously defend itself having "done nothing morally wrong".
Romania striker Mutu was sacked by Chelsea in October last year after failing an FA approved drugs test for cocaine, although the July 12 test referred to by the FA was negative.
The FA said in a statement: "It is alleged that Chelsea FC has breached Regulation 1(e) of The FA's Doping Control Regulations, which states that interference with a drugs test or the Doping Control Programme will be regarded as amounting to a breach of the Doping Control Regulations".
Chelsea responded with a statement saying it was "absolutely committed to the fight against drugs in football. We believe we have demonstrated this by our actions and would never attempt to contravene any rules in order to cover-up drugs in sport.
"We have made it clear publicly that we will adopt a zero tolerance policy to anybody who fails a drug test and rejects the chance of help and rehabilitation when offered by the club.
The FA rules on doping offences state: "The independent private testing/screening of players by clubs, club officials or any other person subject to FA rules is prohibited.
"Such testing/screening will be regarded as conduct that would interfere with The FA's doping control programme...".
Chelsea have taken a hard line against drugs in the past and as well as firing Mutu the club sacked Australia goalkeeper Mark Bosnich in January 2003 after he tested positive for cocaine.
The west London club has until September 23 to respond.
