Blockages – The material cannot be digested properly and can cause what seems like constipation.
Respiratory issues – The material can enter the lungs and cause respiratory problems, which is incurable as antibiotics don’t remove the substance itself. It is a slow and painful death.
Pouch trapping– It can become lodged in the pouch potentially leading to infection.
Choking – There have been many reports of hamsters found dead with fluffy bedding stuck in their mouth blocking their airway.
Limb trapping – It can also be too harsh to pull apart for small creatures, and when they exit their nest to get food or water, their limbs can become trapped. And with their natural instinct, they pull on it until their limbs can get dislocated. Some people have even reported their pets gnawing their own limbs off to free themselves.
The above list is taken from – https://web.archive.org – hamsteradvice.com/ban-fluffy-bedding