Background: Root canal preparation produced a layer called smear layer. Irrigant solution used to eliminate microorganism, debris, and smear layer. Lemon (Citrus limon) peel is one of natural resources that has active compounds to eliminate smear layer from root canal. This study aims to determine the effectiveness of lemon peel (Citrus limon) extract 5%, 10%, 15%, 20% as final root canal treat…