Tymoshenko, a former prime minister, is serving a seven-year jail sentence on charges she abused her authority in a 2009 gas deal with Russian energy company Gazprom.
She faces a slew of other charges, though her Western supporters suspect they are politically motivated. She lost a bruising political campaign in 2010 to pro-Kremlin President Viktor Yanukovych.
Her daughter, Yevhenia Carr, told Radio Free Europe/Radio Liberty last week Tymoshenko had taken ill during her trial and was no longer able to get out of the bed in her prison cell.
Serhiy Vlasenko, Tymoshenko's lawyer, was quoted by the National News Agency of Ukraine as saying his client hasn't seen a doctor in 14 days. She was ordered to have bed rest for unspecified medical ailments in early November. Vlasenko said her mistreatment amounts to torture.
Carr said Ukrainian authorities continued to grill the former prime minister in her prison cell.
"And for the first time in the history of imprisonment, in criminal history, or (in the history) of the prisons of Ukraine, the investigation is carried out in a cell when the person is lying on a prison bed and cannot move," she said.