Ngugi was given a four-year ban in February 1993 for refusing to take a random drugs test. However, the International Amateur Athletic Federation council voted unanimously to lift the last May under their exceptional circumstances rule, saying that Ngugi had suffered enough.
Ngugi, who won the 5,000 metres at the 1988 Olympics, will run in a 10km race round Edinburgh's city centre on Sunday and in the 10-mile Great South Race a week later.
The first race will pit Ngugi against his fellow Kenyan Douglas Wakiihuri, the marathon world champion in 1987 and the winner of the marathon at the World Cup in April.
In the women's race, Liz McColgan takes on Olga Bondarenko of Russia, who beat her in the 10,000m Olympic final in 1988.Reuse content