Athletics at the 1988 Summer Olympics – Men's 100 metres

Johnson was not the only participant whose success was questioned: Lewis had tested positive at the Olympic Trials for pseudoephedrine, ephedrine and phenylpropanolamine. Lewis defended himself, claiming that he had accidentally consumed the banned substances. After the supplements that he had taken were analyzed to prove his claims, the USOC accepted his claim of inadvertent use, since a dietary supplement he ingested was found to contain "Ma huang", the Chinese name for Ephedra (ephedrine is known to help weight loss).[7] Fellow Santa Monica Track Club teammates Joe DeLoach and Floyd Heard were also found to have the same banned stimulants in their systems, and were cleared to compete for the same reason.[8][9]

The highest level of the stimulants Lewis recorded was 6 ppm, which was regarded as a positive test in 1988 but is now regarded as negative test. The acceptable level has been raised to ten parts per million for ephedrine and twenty-five parts per million for other substances.[7] According to the IOC rules at the time, positive tests with levels lower than 10 ppm were cause of further investigation but not immediate ban. Neal Benowitz, a professor of medicine at UC San Francisco who is an expert on ephedrine and other stimulants, agreed that "These [levels] are what you'd see from someone taking cold or allergy medicines and are unlikely to have any effect on performance."[7]

Following Exum's revelations the IAAF acknowledged that at the 1988 Olympic Trials the USOC indeed followed the correct procedures in dealing with eight positive findings for ephedrine and ephedrine-related compounds in low concentration.

Christie was found to have metabolites of pseudoephedrine in his urine after a 200m heat at the same Olympics, but was later cleared of any wrongdoing.[1][10] Of the top five competitors in the race, only former world record holder and eventual bronze medalist Smith never failed a drug test during his career. Smith later said: "I should have been the gold medalist."[11][12]

The CBC radio documentary, Rewind, "Ben Johnson: A Hero Disgraced" broadcast on September 19, 2013, for the 25th anniversary of the race, stated 20 athletes tested positive for drugs but were cleared by the IOC at this 1988 Seoul Olympics. An IOC official stated that endocrine profiles done at those games indicated that 80 percent of the track and field athletes tested showed evidence of long-term steroid use, although not all were banned.

This was the twenty-first time the event was held, having appeared at every Olympics since the first in 1896. For the first time, the number of competitors topped 100.

Algeria, Bahrain, Burkina Faso, Hong Kong, the Maldives, Papua New Guinea, San Marino, Togo, Tonga, Vanuatu, South Yemen, and Zimbabwe appeared in the event for the first time. It was also the first appearance of "Chinese Taipei," though the Republic of China had competed before. The United States made its 20th appearance in the event, most of any country, having missed only the boycotted 1980 Games.

The event retained the same basic four round format introduced in 1920: heats, quarterfinals, semifinals, and a final. The "fastest loser" system, introduced in 1968, was used again to ensure that the quarterfinals and subsequent rounds had exactly 8 runners per heat; this time, the system was used in both the preliminaries and quarterfinals.

The first round consisted of 13 heats, each with 7 or 8 athletes. The top three runners in each heat advanced, along with the next nine fastest runners overall. This made 48 quarterfinalists, who were divided into 6 heats of 8 runners. The top two runners in each quarterfinal advanced, with four "fastest loser" places. The 16 semifinalists competed in two heats of 8, with the top four in each semifinal advancing to the eight-man final.[6][13]

These were the then-recognized world and Olympic records (in seconds) prior to the 1988 Summer Olympics.

World Record	9.831	Ben Johnson	Rome (ITA)	August 30, 1987
Olympic Record	9.95	Jim Hines	Mexico City (MEX)	October 14, 1968

¹ This time was rescinded by the IAAF Council in September 1989 after Johnson admitted to using steroids between 1981 and 1988. Following Johnson's disqualification, Carl Lewis's time of 9.92 was recognized as a new Olympic record, and also became a new world record after Johnson's time was rescinded.

• Women's 100 metres

• Video of Men's 100m Finals, 1960-2000

• (in English) Official Report