Bath's joint captains Michael Lipman and Alex Crockett and winger Andrew Higgins have resigned from the English rugby amid allegations they failed to take drug test on three occasions.
Their decision came immediately before they were to appear at an internal hearing but the players say "scurrilous and unsubstantiated allegations" have forced their exit and that they hadn't refused anti-doping tests.
The Rugby Football Union says it is looking into the matter.
Lipman's played ten tests, the last against the All Blacks in November.
Bath has now lost five senior players in three months. England prop Matt Stevens resigned after being banned for two years in February following a positive test for cocaine.