London  - Disgraced British sprinter Dwain Chambers admits in his forthcoming autobiography "Race Against Me" that he took a concoction of over 300 performance-enhancing drugs.

In an instalment published in Tuesday's Daily Mail ahead of next Monday's release, Chambers, who served a two-year ban after being found guilty of doping offences in
2003, said he had paid out 30,000 dollars a year for doping substances.