During a roundtable in Pennsylvania, Clinton urged women "don't take it personally because it can knock you to your knees if you take it personally."
"The online culture of bullying young women is horrible and even the most confident, well prepared girl has to be worrying, like why are people picking on me? Why are they saying these things about me? What is happening here?" she said. "We have got to stand up against that."
Clinton, who has been in the public eye for much of her adult life, said it has taken her "years to be able to" give this advice because she has to figure out how she chooses to deal with it first.
"Human nature has not changed," Clinton said, "but the megaphones that are now used to trumpet these kinds of attitudes has just magnified this issue."
Clinton and her supporters have been subject to what they see as sustained online bullying from some of Bernie Sanders' most vocal supports to the point that those men have earned the moniker "Bernie Bros."
Sanders' campaign is well aware of the issue. Tad Devine, Sanders' top strategist, disavowed the movement last week, and Mike Casca, Sanders' director of rapid response, has urged his online faithful to cut it out and reached out to Clinton's campaign to apologize.
"if you support @berniesanders, please follow the senator's lead and be respectful when people disagree with you," he wrote.
Clinton's comments about bullying also nod to the fact that should she win the nomination and run against Donald Trump, the current Republican front-runner, both Democrats and Republicans alike feel the contest could be historically dirty. Trump has said that former President Bill Clinton and his sexual history is fair game, should he need to use it against her.
Clinton acknowledged Trump's tactics Friday.
"If I am the nominee, we could very well have a campaign that is exactly all about that," Clinton said of bullying. "Insults, derogatory comments."
Clinton is campaigning outside Philadelphia as part of a sprint towards the April 26 primaries in the Keystone State, as well as Delaware, Connecticut, Maryland and Rhode Island.
Polls show Clinton is up in all five states, but Sanders has focused considerable time trying to cut into Clinton's Pennsylvania lead, given that state is the most delegate rich on Tuesday.