Fifa, the organisation that runs world football, has opened an investigation after Luis Suarez appeared to bite another player during a World Cup game.
Suarez clashed with Italy defender Giorgio Chiellini during Tuesday's Group D game between Italy and Uruguay.
The referee took no action at the time, but Fifa could give him a ban of up to 24 matches or two years.
Suarez and Uruguayan FA have until 5pm Brazil time on Wednesday to respond to the charges against him.
Chiellini claimed Suarez bit him on the left shoulder, but Suarez said the defender "bumped" into him.
The referee took no action during the game but Fifa have now said they're investigating what happened.
Tuesday's match ended in a 1-0 victory to Uruguay, sending them through to the last 16 and knocking out Italy.
Suarez's track record
This isn't the first time Suarez has got into trouble for something like this.
The Liverpool striker was given a 10-match ban by the FA last year for biting Chelsea's Branislav Ivanovic.
In 2010 he was banned for seven games when he was at Dutch side Ajax after biting PSV Eindhoven midfielder Otman Bakkal's shoulder during a match.