From A Wiki of Ice and Fire
Basilisks are said to infest the jungles of Yi Ti . In some places they are used to fight other animals, such as dogs, as wagers are made on the outcomes. A basilisk is able to tear a large dog to pieces.
Basilisks are venomous and are the source of 'Basilisk venom' , a paste spiced with basilisk blood which gives meat a savory scent but which induces a violent madness in any creature with warm blood, whether man or beast. 
A Clash of Kings
References and Notes