South Wales Police confirmed the former Bluebirds midfielder, 35, is alive after rumours of his death spread on social media.
Police were unable to give further details, but it is understood that Whittingham is in critical condition in Cardiff's Heath Hospital.
Whittingham's wife Amanda is currently pregnant.
Whittingham came through the ranks at Aston Villa, where he won the FA Youth Cup in 2002 prior to a Premier League debut a year later.
He won his first of 17 England under-21 caps in 2004 prior to loan spells at Burnley and Derby County, but it was at Cardiff where he really hit his stride following a move to the Welsh capital in 2007.