Bedding refers to the material used to line the floor of the cage. It is generally used to absorb urine and feces, as well as provide a comfortable walking surface and allow for burrowing and nesting. There are many different kinds of bedding; the most commonly used safe ones are covered here.

Bad Beddings:
        1.  Cedar - The oil/phenol that makes the bedding smell nice is toxic and has              been shown to cause problems with the respiratory system as well as the liver.
        2.  Pine - It is soft wood bedding again with a nice smell. It contains less              oil/phenol, it does still have them. There is also kiln-dried pine. The pine has              supposedly had its oils/phenols removed by via kiln-drying. Some people              consider this bedding safe others don't.
        3.  Corn Cob - It has a tendency to mold also animals can coke on the pieces or              ingesting them, causing an intestinal blockage.
        4.  Saw Dust - It is unacceptable bedding. It causes respiratory problems when              inhaled.
        5.  Cat Litter - Most are unacceptable as bedding. Their dusty and again can              cause respiratory problems. Also the clumping litter they can eat the clumps              and can cause a blockage and death.

Good Beddings:
        1.  CareFresh - It's made from environmentally friendly biodegradable fiber; it              contains no ink, clay or chemical contaminants. CareFresh bedding              occasionally harbors parasites (mites and lice) and can be frozen for 24-48              hours before use as a precaution.
        2.  Aspen - It's made up of wood chips like cedar and pine. However, unlike pine              and cedar, aspen is a hardwood not softwood bedding. It lacks the              oils/phenols that pine and cedar have, making it a safe bedding option. Aspen              bedding occasionally harbors parasites (mites and lice) and can be frozen for              24-48 hours before use as a precaution.
        3.  Yesterday's News - This is a cat litter, but it is different. It's made from              recycled newspapers and is thus quite safe.
        4.  Material - You can also use material bedding as well. Especially with the              Ferret Nation and Critter Nation a lot of people use some type of material to              cover the bottom pan and shelves. It's very absorbent and also to clean you              just run them through the wash. There are diff. types of material some hold up              better and are more absorbent. It's personal preference.

Nesting Material: Even non-breeding rats like to nest, as it is one of the natural instincts of a rat to burrow or pile up soft materials to make him or herself a safe and comfortable place to sleep. Providing a smaller portion of a different, softer, kind of bedding can help your rats be comfortable in their beds. CareFresh, while expensive for entire cage bedding, makes good nesting material as it is very soft and absorbent. Shredded paper towels or toilet paper, or strips of a non-fraying material such as polar fleece can also be used.