No, Nooski Refill Rings are not poisonous. They are used in conjunction with the Nooski Mouse Trap. The Nooski Mouse Trap is a humane, safe, clean and easy to use trap. Trapping mice is easy with this innovative design. This trap never misfires and will kill mice quickly and as humanely as possible. The mouse enters the trap and the system releases a rubber latex ring that goes around their neck. This causes the mouse to spring free and then die a few feet from the trap. This is less messy and is safe to use around pets and children. Snapped fingers and poison are no longer a worry with this Nooski mouse trap. These traps are environmentally safe and made from industrial grade plastic. This system is less messy because all you need to do is lift the mouse up and dispose of it.