The aim of this study was to evaluate data on doping controls in racehorses over a given ten-year period, primarily to identify positive findings and to summarise recommendations for the prevention of accidental contamination with prohibited substances, where appropriate. Data on doping controls of racehorses in the Czech Republic from 2010 to 2019 were obtained from the archives of the Jockey Club of the Czech Republic. For each year, the total number of horses starting at races held in the Czech Republic, the number of horses tested, and the results of the doping controls were determined. Data on the type of samples, positive findings and statements from responsible persons about the cause of the positive finding were recorded. During the monitoring period, 11,852 horses competed in races in the Czech Republic and 641 of them underwent a doping control. Blood was taken from 356 horses as the sample for testing and urine was collected from 285 horses. A total of 13 positive findings (2.03% of the 641 tested) were found during the period, namely of morphine, caffeine, theobromine, omeprazole sulphide, furosemide, clenbuterol, norketamine, ritalinic acid, dexamethasone, flunixin, hydroxylidocaine and oripavine. The most common cause, in a total of seven horses, was confirmed as suspected feed contamination. Prevention of positive doping results in our circumstances should therefore be directed primarily towards compliance with proper feed and stable management.