Any bedding designed for Guinea Pigs is safe FALSE
Just because the packaging says the bedding is safe for
cavies does not mean it is. Many beddings are harmful to
cavies and should never be used.
The following beddings do
not make suitable bedding for
cavies:
Cedar
Pine (non kiln-dried or non aired pine)
Cat Litter
Sawdust
Straw
Corn cob or corn kernal bedding
Wheat based bedding
Hay does not absorb and does not make good bedding
Newspaper alone
They are unsafe due to various reasons - some give off certain aromas which can lead to respiratory distress in piggies, while others are dangerous if ingested. Straw in particular is dangerous in physical ways, causing injuries such as pieces stuck in the eye.
There are lots of safe bedding alternatives: Aspen, Kiln-dried Pine (or plain pine aired out for a few days), CareFresh, Megazorb/Cell-sorb, Fleece, Towels and Vetbed amongst others.