Since rabbits will nibble on their litter and dusty litters can be inhaled, it's important to choose a litter that is non-toxic. Aspen pellet or shavings offer good odor control and are highly absorbent. Litter made from paper pulp or recycled paper is dust-free and is also a good choice. There is a pellet litter called Cat Country, made from plant fibers that works well also. Don't use clay cat litter or clumping litter as they pose dangers for rabbits.