Players will undergo blood tests next season as part of UEFA's new anti-doping detection regime in all competitions run by European soccer's governing body.
Until now UEFA has only conducted blood tests at international tournaments - Euro 2008 and 2012. From this month the detection regime is to be extended to the Champions League and Europa League.
Checks will be made in and out of competition and players may be asked at doping controls to give urine samples, blood samples or both.
However, UEFA said on its website (www.uefa.com) that out-of-competition checks would only be carried out if players or teams had not informed testers where they would be when required to be tested.
The new rules follow a UEFA anti-doping panel meeting held late last year.
At the meeting, chairman Dr Jacques Lienard said: "We cannot say that football is free of doping. It is important UEFA remains vigilant in its fight against doping and all products that are associated with doping".
The panel was told Euro 2012 was drug-free after comprehensive pre-tournament testing of all 16 teams followed by a full in-competition programme.
Players preparing for the European Women's Under-17 Championship were last week given a stark warning against drug-taking.
UEFA anti-doping assistant Richard Grisdale said: "If you make a mistake or don't know the rules and you test positive, you will be banned. You will suffer. Your team can suffer."
He added that doping was "cheating the team you're playing against and cheating your team mates".
Grisdale said: "You are responsible for everything in your body. If you test positive, you cannot blame somebody else. Take responsibility for the medicines you take, any supplements, what you eat, what you drink."
(Writing by Tony Goodson; editing by Tony Jimenez)