Loc had just finished a song in Des Moines when he collapsed, TMZ.com said.
He was attended to for five minutes on stage before the audience was asked to leave.
TMZ.com said his current condition is not being released.
In 2009, Loc collapsed on stage and was rushed to a Florida hospital, and in 2011, he was hospitalized for exhaustion after collapsing again.
In June 2012, he collapsed on stage from heat exhaustion, TMZ.com said, and in August 2012, suffered from a seizure while watching a comedy show.
Loc once allegedly told police who suspected him of a DUI that he had a seizure while driving, TMZ.com said.