Former Russian Prime Minister Yegor Gaidar was released from a Moscow hospital this evening following a mysterious illness, his spokesman said.
Doctors could give a final diagnosis of what struck the 50-year-old economist as early as tomorrow morning, spokesman Valery Natarov said.
Mr Gaidar who served briefly as prime minister in the 1990s under President Boris Yeltsin and is a leader of a Russian liberal opposition party - began vomiting and fainted during a conference in Ireland on November 24th, and was rushed into intensive care at an Irish hospital.
He fell ill a day after ex-KGB officer and Kremlin critic Alexander Litvinenko died in London after being poisoned with the radioactive element polonium 210.
Mr Gaidar's aides initially said doctors treating him in Moscow suspected he had been poisoned and were working to determine how that might have happened. Irish doctors concluded he was not poisoned by a radioactive substance, but said his health had suffered sudden "radical changes".
The illness added to growing speculation in Moscow over Litvinenko's death and who might be responsible. Some critics have tied Litvinenko's death and Mr Gaidar's poisoning to the murder of Russian investigative journalist Anna Politkovskaya, also a Kremlin critic.
A top official with Mr Gaidar's party, the Union of Right Forces, said today that he believed Mr Gaidar had been poisoned.