I'm like you, I've heard not to use it but haven't done any research to find out why until now.

Kevin's book says "Do not use bedding that containes cedar - the oils in cedar are TOXIC to reptiles." The Barkers' new book says "A word or caution: never use cedar shavings in a snake cage. For that matter, never use any strongly scented wood shavings in a snake cage." In the book "What's Wrong with My Snake?" by John Rossi, DVM, MA the author states "A chemical irritant such as that found in cedar shavings and cigarette smoke, high ammonia levels in dirty cages or an allergen such as the dust on corncob litter may produce mild sinusitis, with consequent respiratory signs."

Still not very clear: goes from toxic to mild respiratory problems. Anyone else have any thoughts?