Cedar is a type of softwood that contains natural oils that can be harmful to small animals. These oils can cause respiratory problems, skin irritation, and even liver damage. In addition, cedar shavings can be dusty and can cause eye irritation. For all these reasons, it is best to avoid using cedar shavings for teddy bear hamsters or other small animals.
There are many other, safe bedding materials available for use with teddy bear hamsters such as Aspen shavings, paper-based bedding, and reclaimed paper.