Glass bottles can break. Bottles should be inspected before each use for sharp edges and fragments or flakes of glass that may have become dislodged and are loose inside the bottle. Do not use bottles if there are any cracks of chips on the bottle. Sudden temperature changes can cause glass bottles to crack or break. Be sure bottle and liquid are same temperature when filling or warming. Do not use a microwave oven to heat the bottle because microwave ovens can create hotspots in milk or formula. Always test temperature of liquid before feeding baby. This bottle may only be used with adult supervision. Do not let child feed themselves with glass. Do not let child walk with glass. Do not let a child take a bottle to bed. Before first use, sterilize bottle, nipple and parts by leaving them in boiling water for five (5) minutes. After every use, bottle, nipple and parts should be washed thoroughly with hot, soapy water.