THE SEOUL OLYMPICS; Johnson Loses Gold to Lewis After Drug Test

Ben Johnson of Canada, who won the Olympic 100-meter final Saturday in the world-record time of 9.79 seconds, was stripped of his gold medal and today was disqualified from the Games after drug tests showed he had used an anabolic steroid.

The International Olympic Committee announced the test results this morning, and later in the morning, the International Amateur Athletic Federation, the world governing body for track and field, banned Johnson from competition for two years, the maximum penalty. The Canadian Government banned him for life from receiving a monthly payment he had been receiving from it.

The I.A.A.F. also said that Carl Lewis, who set an American record of 9.92 seconds when he finished second Saturday, would be elevated to the winner's position. Linford Christie of Britain will now get the silver medal, and Calvin Smith of the United States will receive the bronze.

Johnson's positive test is likely to have wide and profound, but quite different, implications for him and for the Olympics.

James Worrall, an I.O.C. member in Canada, said that Johnson ''has been killed'' as an athlete, and that the sprinter's once-favored status as a hero to many sports fans in Canada, in Jamaica, where he was born, and around the world will now be tarnished.

For the Olympics, however, the finding served as a symbolic victory over those who would cheat to win.