Rounded Nylon bristles (SOFT) for superior cleaning. Ergonomic handle made from 100% Corn Starch NON GMODisposal Instructions:1. Break off toothbrush head.2. Discard thoughtfully. Check with local recycling programs if suitable (Nylon is recyclable). 3. Place the rest of the toothbrush into your compost.Typically takes 90 days to break down in a commercial compost. You have made the right choice - any way you dispose of this, you can be sure that these toothbrushes will not be land-fill for millions of years to come - unlike many toothbrushes in use today.