Former Ukrainian prime minister Yulia Tymoshenko's health has deteriorated during her hunger strike, her daughter said.
Yevgenia Tymoshenko said the family is hoping the government will take action so she will stop the protest.
Yevgenia told reporters in Prague today that the family now believe Yulia, serving a seven-year jail sentence on charges of abuse of office, needed treatment for her back outside Ukraine.
Ms Tymoshenko's jailing has soured Ukraine's ties with the European Union and risks becoming an embarrassment when it co-hosts the European football championship in June.
European leaders have already threatened to boycott the tournament and several have called off visits to the country, now ruled by her political rival Viktor Yanukovich.
The EU has condemned Ms Tymoshenko's conviction as an example of selective justice.
It warned Ukraine that its members would not ratify agreements on political association and free trade as long as she remains in prison.
Ms Tymoshenko has been on hunger strike since last week after she said prison guards beat her during a forced transfer to a hospital for examination of her long-term back problems.
"We are really running out of time. I don't know how long my mother can be on hunger strike, whether it can be five days or ten days, we are not sure," Yevgenia Tymoshenko said.
Speaking alongside her father, who lives in the Czech Republic, Yevgenia said she visited her mother in jail two days ago.
She said: "She was very weak and her physical condition is worsening. When they attacked her, it caused more pain to her back.
"Now she is in real pain, she is almost all the time lying down. She cannot move much but that is also because she is weak from the hunger strike.
"We are really hoping there will be some strong positive changes in the actions of the regime towards political prisoners so that she can stop the hunger strike as soon as possible."
Prison authorities have denied Ms Tymoshenko's allegations that she was beaten, but Ukraine's senior human rights official said that Ms Tymoshenko was bruised.
President Yanukovich has ordered an inquiry of the alleged beating.
The German government has offered to treat Ms Tymoshenko in a German hospital, a move that could remove her from Ukraine for the time of Euro 2012, but it is not clear if the government or Ms Tymoshenko would agree.
Yevgenia said the family now saw treatment abroad as the only possibility.
She said: "After she has been forcefully taken to hospital, I understand she cannot trust people in the hospital because it was not her choice.”
She said the football tournament could be a chance for Mr Yanukovich to change tack.
"The Euro 2012 is a real chance for Yanukovich and his government to start moving in the direction of fulfilling the demands of the parliamentary assembly of the council of Europe and the whole democratic world," she said.
German Chancellor Angel Merkel has linked her visit to Ukraine to Ms Tymoshenko's fate, an aide said.
European Commission President José Manuel Barroso will also not visit Ukraine while Ms Tymoshenko is in prison.
German President Joachim Gauck and Czech President Vaclav Klaus have cancelled plans to visit a May summit.