All horses that ran in the Breeders' Cup have tested negative for illegal performance-enhancing drugs.

The California Horse Racing Board said testing was completed Tuesday and all the samples came back clear from the UC Davis laboratory.

All entrants underwent pre-race blood testing for TCO2, a performance-enhancing alkalizing agent known as a "milkshake," while post-race blood and urine testing was done on the top three finishers in all 14 races plus random horses selected by the stewards at Santa Anita.

The tests checked for more than 45 anabolic steroids and hundreds of other prohibited drugs.

Out-of-competition testing was also done on 25% of all horses pre-entered in the two-day world championships, with samples analyzed in Europe for international entries.