Germany's anti-doping law has come into effect with offending athletes facing up to three years in prison and those behind them up to 10 years.
The law was earlier passed by the German parliament's lower and upper houses, and signed by the nation's president, Joachim Gauck.
"The law was overdue, important penal provisions now come into effect," said Interior Minister Thomas de Maiziere, whose portfolio includes sport, on Friday.
"I am convinced that we can tackle doping in sport and the criminal structures behind it more effectively with this anti-doping law," De Maiziere said, naming it "a clear commitment of Germany for clean and fair sport".
Athletes who dope themselves or are in possession of performance-enhancing drugs face criminal proceedings with sanctions including one to three years behind bars.
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Those who traffic and prescribe doping substance can be jailed for 10 years in severe cases.
The German Olympic sports confederation had voiced reservations in connection with the law and the independence of sports jurisdiction.
But Justice Minister Heiko Maas said sports jurisdiction alone had not proven to be an effective deterrent.
