From a press release issued by the FIM:

Road Racing World Championship Grand Prix
Anti-doping controls

Anti-doping controls were carried out at the Spanish Grand Prix, held on the circuit of Jerez, on May 2 last.

All the samples tested showed the absence of any banned substances.

The riders controlled were: Sete Gibernau (SPA, MotoGP), Valentino Rossi (ITA, MotoGP), Carlos Checa (SPA, MotoGP), Marco Simoncelli (ITA, 125cc), Andrea Ballerini (ITA, 125cc), Andrea Dovizioso (ITA, 125cc).