Ron Paul, the former Republican representative who ran for president three times, was hospitalized on Friday in Texas for "precautionary" reasons, Fox News has learned.
Paul, 85, was speaking about the free market during a livestream on his YouTube channel when his speech began to slur earlier in the day.
His son, Kentucky Sen. Rand Paul, did not immediately respond to a Fox News' request for comment.
Paul served as a Texas congressman for 23 years over a 36-year period and made three unsuccessful bids to become president: in 1988 as a libertarian and twice in 2008 and 2012 as a Republican.
Paul, a leader of the nation's libertarian movement, retired from Congress in February 2013, although he continued to remain active in politics.
Lawmakers responded to the news with an outpouring of support for Paul.