His family said in a statement the 89-year-old McGovern was being evaluated for "brief transient spells where he passes out and becomes verbally unresponsive," CNN reported.
He was admitted to the hospital Tuesday where he was resting comfortably and undergoing tests, the family said.
A nursing supervisor for Flagler Hospital in St. Augustine, Fla., told CNN McGovern was in fair condition.
In December, McGovern was rushed to a hospital in his native South Dakota after falling at a university.
McGovern is best known for his unsuccessful 1972 presidential bid as the Democratic nominee against incumbent Republican Richard Nixon. He represented South Dakota in the U.S. House and Senate before his presidential run. He left politics after losing a 1980 bid for a fourth Senate term.
McGovern was appointed by President Bill Clinton as an ambassador to the U.N. Food and Agriculture Organization and was appointed in 2001 as the U.N.'s first global ambassador for hunger.