The Paraguay international spat at Wolves defender Richard Stearman during yesterday's clash at the Molineux which the home side won 3-1.
Alcaraz could be banned for three matches if he is found guilty of the charge.
"The incident, which was not seen by the match officials but caught on video, relates to his side's game against Wolverhampton Wanderers [yesterday].
"The player has until 6pm on November 8, 2011 to respond to the charge. If the player admits the charge he may accept an automatic three match suspension."