A Winehouse spokesman said she will be cancelling an appearance in Istanbul tomorrow and in Athens on Thursday.
The spokesman said ehat Winehouse would like to say sorry to fans expecting to see her, but "feels that this is the right thing to do."
He added that she will return home after agreeing with management that "she cannot perform to the best of her ability."
The singer, who has publicly struggled with drugs and alcohol, was jeered late on Saturday as she performed in Serbia's capital Belgrade.
She stumbled onto the stage, mumbled through her songs and sometimes wandered off.