Bill Clinton was interrupted by a heckler who accused him of being a rapist during a speech at a campaign rally in Milwaukee.
The former US president began his sentence by saying: "No one can dispute the fact..."
But he was interrupted as he took a pause by a protester who shouted: "That you're a rapist!"
Another audience member then repeatedly shouts: "Bill Clinton is a rapist!"
Mr Clinton's supporters shouted down the hecklers and removed them from the rally.
"Thank you," Mr Clinton said. "You've gotta feel sorry for them. They had a bad day yesterday so they're trying to make it up."
He went on to say: "This is what is the matter with politics.
"When other people pour poison down your throat but don't drink it. Give back good."
The interruption comes after Donald Trump apologised for saying he could do anything with women, including groping them without consent.
In his video apology, Mr Trump threatened to raise the former president's infidelities.
“Bill Clinton has actually abused women and Hillary has bullied, attacked, shamed and intimidated his victims,” he said.
“We will discuss this more in the coming days. See you at the debate on Sunday.”
Mr Trump later retweeted posts by Juanita Broaddrick, who claims Mr Clinton raped her in 1978.
Ms Broaddrick's accusations were never tested in criminal court.
Mr Clinton has long denied the allegations and Ms Clinton has declined to address them.
