Turkey forward Colin Kazim-Richards was allegedly caught spitting at a Portuguese player during their opening Euro 2008 match.
At Euro 2004, Italy's Francesco Totti was suspended for three games after spitting at Danish player Christian Poulsen during a group game.
UEFA charged Totti with "gross unsporting conduct" after the Danish federation filed a complaint against the Roma star.
The Portuguese Football Federation has not commented on this matter as of yet.