Toothbrushes that claim to be "natural" and "bamboo" are usually just referring to the handle and the bristles are still plastic -being scrubbed into your mouth and gums! These toothbrushes from Answers by Nature are ultra soft and luxurious, with plant-based bristles that make the entire toothbrush 100% biodegradable. Health and Earth Friendly. Natural Bristle Toothbrush [4-pack], Ultra Soft Castor Bean Bristles, 100% Biodegradable, Plant Based Bristles and Bamboo Handle, Answers by Nature