England flanker Michael Lipman and two of his former Bath team-mates are "surprised and disappointed" to have been charged with drugs offences by the Rugby Football Union.
The governing body have accused Lipman, Alex Crockett and Andrew Higgins of conduct prejudicial to the interests of the game "including taking prohibited substances and wilful refusal to take a drugs test", following an end-of-season celebration in London.
The trio, who deny the charges, had avoided a Bath disciplinary hearing on similar charges when they terminated their club contracts on June 1.
Australian lock Justin Harrison has also been charged by the RFU but he left Bath following allegations stemming from the same evening and has since retired.
Sports solicitor Richard Mallett released a statement on behalf of Lipman, Crockett and Higgins which said: "We are extremely surprised and disappointed both by the RFU's decision to convene a disciplinary panel and the terms of their statement.
"Any charges brought by the RFU will be vigorously contested.
"This is a matter that we take very seriously and will do everything possible in order to clear our names.
"For legal reasons we are unable to comment further at this stage."
If the panel finds against them, Lipman, 29, Crockett and Higgins, both 27, could receive longer bans than the two-year suspension given to their former Bath team-mate Matt Stevens, who admitted taking cocaine.
The RFU statement, announcing the charges, read: "We can confirm we will be asking the players to appear before an RFU disciplinary panel charged with conduct prejudicial to the interests of the game (rule 5.12) on a number of charges including taking prohibited substances and wilful refusal to take a drugs test.
"All details of the investigation now form part of the disciplinary process and to protect the integrity of the process will remain confidential.
"The RFU will make a further announcement when the panel has been convened and a date has been set but can confirm we intend to call a number of players, club management and other third parties to appear before the panel to support the case."
Bath chief executive Bob Calleja also issued a statement, saying: "The club treats matters relating to drugs very seriously and we are perfectly satisfied that we acted correctly in requiring the players to explain themselves at an internal disciplinary hearing.
"They chose not to do so and, so far as we are concerned, our internal process is at an end, the players no longer being employed by the club."