The 64-year-old won 10 events on the European Tour as a player but is best known for his association with the Ryder Cup tournament.
Gallagher played in the event eight times as a player and was captain of the European Team in 1991, 1993 and 1995.
That was considered a golden era for the competition with Europe losing narrowly in the first two events before famously winning at Oak Hill in 1995.
His daughter Kirsty is also a familiar face on television and currently works as a presenter on Sky Sports News.
He is currently being treated at the Aberdeen royal infirmary.
The European Tour's chief executive George O'Grady said: "We are in touch with Bernard's wife, Lesley, and the Gallacher family and, obviously, we join with everyone in wishing Bernard a speedy recovery."
His nephew Stephen, who plays on the European Tour added: "I understand that he is critical but stable. My family is in disarray at the moment and it is obviously a worrying situation. We are all anxious."
Gallacher was awarded an OBE in 1996.
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