Inspect nipple immediately before and after each use and throw away when worn, damaged or punctured, for example by biting. Before use, wash thoroughly and sterilize in an Avent electrical or microwave steam sterilizer, in sterilizing solution following the manufacturer's instructions, or by boiling in water for at least five minutes. Always wash immediately after use. Keep in a dry, covered container. Do not leave in sunlight when not in use. Infants must not be bottle fed without adult supervision. Feeding nipples should not be used as dummies, pacifiers, or soothers. Continuous sucking on a bottle may cause tooth decay. Do not use with Avent Disposable System. Use clear nipples with reusable bottles and blue nipples with disposable nursers.