Ashton, 29, is alleged to have bitten Northampton prop Alex Waller during Saturday's Premiership victory.
The two incidents occurred in the 24th and 25th minutes of the game at Allianz Park, which Saracens won 27-12.
Ashton's mouth appeared to make contact with Waller's hand during a tangle on the floor.
Ashton, capped 39 times by England, was banned for 10 weeks last season for making contact with the eye area of Ulster back Luke Marshall during a European Champions Cup game.
If the biting charge is proved, he could face another lengthy lay-off and a setback to his prospects of an international recall in the season ahead.
Ashton was ruled out of this year's Six Nations because of suspension and was left out of the squad which toured Australia last summer.
His last England appearance came back in the summer of 2014, against New Zealand.
Saracens winger Chris Ashton has been charged with two acts of biting and will appear before a Rugby Football Union disciplinary panel on Tuesday.