Here's what Red Horse Products has to say:
"Hoof-Stuff is an antifungal and antibacterial hoof pack for plugging holes and cracks in equine hooves.
Containing only naturally occurring ingredients Hoof-Stuff is non-toxic, safe and easy to use. Its ability to stay in crevices due to its fibrous content allows it to act for longer than other packs and potions. Hoof-Stuff has been found useful for toe holes, white line cracks, central sulcus crevices, abscess cavities, grass cracks among other issues. It's active ingredients act not only to eliminate detrimental fungi and bacteria but also support natural healing and restoration of healthy tissue.
Honey makes fantastic base for this product increasing its antibacterial, antifungal and antiseptic powers and aiding adhesion into the hole!
Hoof-Stuff is advised for use in deeper, tighter holes in the hooves where it is deemed fabric would stay. With shallower holes Artimud is advised instead."