The Bamboo Brush is a sustainable Bamboo toothbrush delivered to your home at dentist recommended intervals. The bristles are made from Nylon. Although some manufacturers claim their bristles are 100% biodegradable, in most cases they aren't. The only biodegradable material available today is pig hair, but The Bamboo Brush Federation likes animals so they hope we understand that for them this is no option. They will continue to work closely with their manufacturers to seek alternatives. Until then, remove the bristles for proper disposal.