Chief executive Peter Kenyon has pledged that Chelsea will sack any of their players caught taking drugs.
Kenyon's hardline stance follows the club's sacking of striker Adrian Mutu after his positive test for cocaine.
Kenyon told BBC Radio Five Live's Sportsweek programme: "We are absolutely confident there isn't a drug-taking problem within Chelsea.
"If any of our players fail a drugs test our contracts are clear - we will take the same position."
Mutu faces a ban of between six months and two years when the Football Association decides on his punishment.
Chelsea decided to act before his case was heard and sacked the striker on the grounds of gross misconduct.
The club have been criticised for their stance over Mutu, with the Professional Footballers'
Association accusing the club of failing in their duty of care to the player.
Chelsea have also been accused of being too eager to sack Mutu and critics have suggested that the club would have taken a different course of action had other first-team players been caught taking drugs.
But Kenyon defended the club's decision and added: "We can take that position because the support mechanisms around our players are excellent.
"The players have a role to play in this. It's a two-way process.
"Players are given ample opportunity and support these days - we fully buy-in and support the PFA's education programmes.
"The same support was there for Adrian Mutu. He chose to ignore it and lie and as a consequence the rules are quite simple.
"To suggest there was no support and we left him out to dry because we wanted to get rid of him is absolute rubbish.
"During the close-season 14 players left Chelsea and seven came in, along with a new manager.
"The nucleus was there to be a part of our first-team squad and compete in every competition.
"We could have taken the decision to move him out and get a transfer fee but we chose to embrace him as we wanted him to part of our squad."