On August 6th, 1998, Michelle Smith de Bruin was suspended for a period of four years by the Doping Panel of the Federation Internationale de Natation Amateur (FINA). The Irish swimmer was found to have committed a doping offence under the FINA Doping Rules prohibiting the "use of substances and methods which alter the integrity and validity of urine samples used in doping control". The IOC-accredited laboratory in Barcelona had carried out the analyses and found an unequivocal sign of adulteration of the samples "A" and "B" provided by the swimmer with alcohol in a concentration higher than 100 mg/ml.

On September 2nd, 1998, Michelle Smith de Bruin submitted an appeal to the Court of Arbitration for Sport (CAS) and requested the annulment of the decision pronounced by the FINA Doping Panel. Three CAS arbitrators were appointed to decide this case: Mr Yves Fortier (Canada), President, The Hon Michael Beloff QC (England) and Mr Denis Oswald (Switzerland). The parties, five witnesses and one expert-witness were heard by the panel of arbitrators in Lausanne on May 3rd and 4th, 1999. It was the first time in the history of the CAS that a hearing was made public.

After deliberating, the panel decided to dismiss the appeal brought by Michelle Smith de Bruin and to confirm the four-year ban pronounced by the FINA Doping Panel. The arbitrators considered that the appellant did not succeed in convincing them (1) that the samples which were tested were not hers and/or (2) that a third party manipulated the samples in order to adulterate their content.

Regarding this last question, the panel did not accept the appellant's contention that the burden of proof lay upon the FINA to eliminate all possibilities other than manipulation by the Irish swimmer. Based on the facts of the case and the evidence before them, the arbitrators were of the opinion that the FINA had convinced them that the appellant was the only person who had the motive and opportunity to manipulate the sample.