China will take every possible measure to ensure their track and field athletes drug free in their preparations for the Athens Olympics Games, said Feng Shuyong, head coach of the Chinese national team.

"We always take strict measures to crack down on those who risks taking banned drugs. But I cannot guarantee no athlete takes banned drugs because you can never ensure a crime-free society even though the law is always there," Feng told reporters at a press conference Wednesday.

The national team has invited some experts to give lessons on how serious damages banned drugs can do to athletes' health.

"All the athletes think that the lessons are very useful and instructive," Feng said.

He added that the athletes have been asked not to eat outside the national team or accept food or drinks from outside the training camp.

"They are also told not to buy medicine from drug stores when felling ill," he said. "Only the team doctors can be trusted."

"They must take very measure to avoid mistakenly taking any banned drugs," he added.