Dylan Hartley has been cleared of any wrongdoing after he allegedly bit Leicester Tigers hooker Tom Youngs on Saturday.
The Rugby Football Union confirmed on Sunday that citing officer Wade Dooley reviewed the match footage and opted against taking any action.
The lack of evidence to support Youngs' claim and absence of any complaint from Leicester have led to Dooley's decision.
"The incident has been reviewed and no action will be taken against Dylan Hartley," said an RFU spokesperson.
Youngs reported the incident to referee Wayne Barnes during Leicester's 22-16 win over Northampton on Saturday.
Leicester boss Richard Cockerill and Northampton director of rugby Jim Mallinder both conceded that it was difficult to spot any evidence of the incident, which could be reported by the citing commissioner.
It may however be a case of Hartley's track record working against him. Hartley was banned for eight weeks in 2012 after biting Ireland flanker Stephen Ferris in the Six Nations.
"Tom said that he was bitten on the hand by someone he didn't elaborate on," said Cockerill.
"The referee referred it to the TMO, and looked at it and there was clearly nothing to look at. Maybe Tom was mistaken. It will be looked at by the relevant people."
Mallinder added that he would be discussing the incident with Hartley, who was famously sent off and suspended for 11 weeks against Leicester in last season's Premiership Final.
"I don't think there was anything in it. I would be very surprised," said Mallinder.
"I haven't looked into it, I have just come off the field. I will be speaking to Dylan about the incident.
"I would be very surprised. I have not spoken to Dylan about it, but I will do."
There was further controversy at the final whistle with Leicester down to 13 men, as Barnes ended the match with some time left on the clock and with Saints in a promising attacking position.
"There was time on the clock. Their (Leicester's) physio got his hands on the ball, Ben Foden got the ball off him and there was still time on the clock," stated Mallinder.
"We were pretty disappointed, 15 against 13, not to have a line-out five metres out."