Ashton charged with two counts of biting
He will appear before a disciplinary panel on Tuesday.
The 29-year-old, capped 39 times by England, is alleged to have bitten Northampton prop Alex Waller during Saturday's 27-12 Premiership victory for champions Saracens.
If the charge is proved, Ashton could be facing a lengthy ban which would damage his hopes of an England recall.
The two incidents occurred in the 24th and 25th minutes of the clash at Saracens' Allianz Park ground in north London, with Ashton's mouth appearing to make contact with Waller's hand during a clash on the floor.
Northampton Director of Rugby Jim Mallinder said after the game that Waller told him he had been bitten on the hand.
Saracens boss Mark McCall, asked about the incident after the match, said he had not seen it.
"These things will run [their] course. I suppose there is a good chance that Chris will be cited as a result, so we will see what happens," he added.
Ashton received a 10-week ban last season for making contact with the eye area of Ulster back Luke Marshall during a European Champions Cup game, although he maintained his innocence throughout.
He was ruled out of this year's Six Nations because of suspension and was left out of the 2015 World Cup squad, when England hosted the tournament.
His last England appearance came against New Zealand in 2014.
Agence France-Presse
