The extent of drug abuse in mass sport is only poorly documented. Studies about drug abuse investigated only the prohibited substances according to the Olympic movement antidoping code. So for instance about the use of anabolic androgenic steroids (AAS) by school children or young students. But only few investigations point to the drug abuse in mass sport regarding the easily accessible over-the-counter drugs of the class of nonsteroidal anti-inflammatory drugs (NSAID). These drugs permit an athlete to compete at his normal level of performance despite injuries or pain. However, the masking of pain may exacerbate the injury. Precautions should be taken to prevent the unwarranted or unmonitored use of anti-inflammatory agents during treatment of sport injuries. The abuse may be extensive since most people consider over-the-counter drugs, such as aspirin and ibuprofen, harmless. Studies in Switzerland among endurance athletes in mass sport examining the use of medications before an event showed a prevalence between 5 and 10% of NSAID. Even if this seems a small number, further investigations should focus on the use of medications among different age groups and preventive information to abstain from the use of certain medication for competitors in mass sport should be worked out.