The former Italian Prime Minister was admitted to hospital on Tuesday morning but has since said he is "fit and ready for this election campaign."
Italy's former prime minister Silvio Berlusconi missed a campaign event on Tuesday after being admitted to the hospital for severe kidney pain.
The leader of the conservative Forza Italia party, 82, is currently running in the EU parliamentary elections to be held on May 26.
He was admitted in Milan's San Raffaele hospital at around 10:00 CEST for renal colic — a pain caused by kidney stones.
His party initially said he would resume his campaigning later in the day, but the former leader did not attend an event scheduled in the afternoon.
Forza Italia deputy leader Antonio Tajani, who is also the current president of the EU parliament, explained in a Facebook video that doctors had advised Berlusconi not to attend.
"Berlusconi is committed to the electoral campaign and will take part in TV shows," Tajani also said.
In a tweet posted in late afternoon, Berlusconi thanked people for their support, adding: "I'm fit and ready for this election campaign!