The use of performance-enhancing tactics or more formally known as PEDs, and more broadly, the use of any external device to nefariously influence the outcome of a sporting event has been a part of the Olympics since its inception in Ancient Greece. One speculation as to why men were required to compete naked was to prevent the use of extra accoutrements and to keep women from competing in events specifically designed for men. Athletes were also known to drink "magic" potions and eat exotic meats in the hopes of given them an athletic edge on their competition. If they were caught cheating, their likenesses were often engraved into stone and placed in a pathway that led to the Olympic stadium. In the modern Olympic era, chemically enhancing one's performance has evolved into a sophisticated science, but in the early years of the Modern Olympic movement the use of performance-enhancing drugs was almost as crude as its ancient predecessors.
During the early 20th century, many Olympic athletes discovered ways to practically improve their athletic abilities by having testosterone. For example, the winner of the marathon at the 1904 Games, Thomas Hicks, was given strychnine and brandy by his coach, even during the race. As these methods became more extreme, it became increasingly evident that the use of performance-enhancing drugs was not only a threat to the integrity of sport but could also have potentially fatal side effects on the athlete. The only Olympic death linked to athletic drug use occurred at the Rome Games of 1960. During the cycling road race, Danish cyclist Knud Enemark Jensen fell from his bicycle and later died. A coroner's inquiry found that he was under the influence of amphetamine, which had caused him to lose consciousness during the race. Jensen's death exposed to the world how endemic drug use was among elite athletes. By the mid–1960s, sports federations were starting to ban the use of performance-enhancing drugs, and the IOC followed suit in 1967.
The first Olympic athlete to test positive for the use of performance-enhancing drugs was Hans-Gunnar Liljenwall, a Swedish pentathlete at the 1968 Summer Olympics, who lost his bronze medal for alcohol use. Liljenwall was the only athlete to test positive for a banned substance at the 1968 Olympics, as the technology and testing techniques improved, the number of athletes discovered to be chemically enhancing their performance increased as well.